In the wake of the September 11 terrorist attacks, the United States attempted to co-ordinate an ambitious plan to curtail the movement and funding of terrorist organisations around the world.

The state department issued its Terrorist Exclusion List, which identified around 40 groups whose members would be excluded from US territory. The Treasury also produced a list of terrorist groups and supporters whose assets would be frozen. In particular, the department identified 21 groups and individuals allegedly linked to the al-Qaeda network; their assets were blocked in co-ordination with 66 other countries. The European Union followed suit, producing a list of 27 groups and individuals.

The lists proved very contentious, with many in the Arab world arguing that the focus on Muslims was far too great. Israel argued the opposite - that prominent Palestinian groups had been ignored. Subsequently a number of Palestinian and loyalist and republican groups in Northern Ireland have been added.

Below is an outline of seven terrorist groups included on the lists.

Abu Sayyaf Group (ASG, Philippines)

The most radical of a number of groups seeking a separate Islamist state in the southern Philippines. The group's presence has been pivotal in shaping the Philippine government's response to the war on terror.

Abu Sayyaf was formed after a split in the Moro National Liberation Front in 1991 and is believed to have around 200 core fighters, with the potential to call on several thousand mercenaries, according to the US State department. The group engages in kidnappings and has been responsible for bombings and assassinations. In 2000 it kidnapped more than 30 foreigners in the Philippines, and in 2001 it expanded the scope of its operations and abducted foreigners from two Malaysian resorts.

The Philippine government has taken an increasingly hard line against the Abu Sayyaf and in 2000 the military launched a sustained assault on one of its strongholds on Jolo Island, during which a number of hostages were freed.

The group is believed to be supported by a variety of Islamic extremists in the Middle East and South Asia, with the Philippine government saying it has received arms, training and other logistical support from the al-Qaeda network.

The Philippines was the first country outside Afghanistan to see US troops deployed in the war on terror. Up to 600 troops will eventually be sent to train and support the Filipino military in its fight against the Abu Sayyaf and other Islamic insurgents.

Armed Islamic Group (GIA, Algeria)

Along with the splinter group, Salafist Group for Call and Combat (GSPC), the Armed Islamic Group is said to be responsible for the deaths of 100,000 people. It aims to overthrow the current Algerian regime in order an Islamic state.

The GIA began a violent campaign in 1992 after an electoral victory for the Islamic Salvation Front was overturned. The group's targets are civilians and government workers and, since 1993, foreigners living in Algeria. Most expatriates killed have been Europeans.

In 1994 the group hijacked an Air France flight to Algeria and in 1999 a French court convicted a number of GIA members for a series of bombings in France in 1995.

The GSPC now rivals the GIA, although both groups reject an amnesty offered by Abdelaziz Bouteflika, the Algerian president.

A number of Algerians have been implicated in the September 11 attacks but there is no evidence of any links to either of these groups.

Hizbollah (Party of God/Islamic Jihad, Lebanon)

The group was formed in Lebanon and is strongly opposed to Israeli and Western interests. It is suspected of involvement in the 1983 bombing of the US embassy, which killed 63 men, and and an attack on US Marine barracks in Beirut, which left 241 servicemen dead.

Subsequently it has been implicated in high-profile attacks on Israeli interests abroad, including bombings in Argentina of the Israeli embassy in 1992 and the Israeli cultural centre in 1994.

Hizbollah is said to have cells in Europe, Africa, Asia, North America and South America, and to have received close support from Iran.

While Lebanon has been equivocal about the war on terror, it believes Hizbollah is a legitimate movement fighting against Israeli occupation of Palestinian territories and as a consequence refused to meet US demands that it freeze its assets.

al-Jihad (Egyptian Islamic Jihad, Egypt)

Active since the late 1970s, the group is thought to be closely aligned to al-Qaeda. Indeed, Osama bin Laden's deputy and physician is Ayman Al-Zawahiri, the founder of the group. He has been indicted by the US for his alleged role in the 1998 bombings of the US embassies in Nairobi and Dar-es-Salaam which have been attributed to al-Qaeda.

al-Jihad's aims are to replace the Egyptian government with an Islamic state, as well as to attack US and Israeli interests on home and foreign soil.

It claimed responsibility for a string of high profile attacks, including the 1981 assassination of Egyptian president Anwar Sadat and the attempted assassinations of interior minister Hassan al-Alfi and prime minister Atef Sedky in 1993. The group was also responsible for the bombing of the Egyptian embassy in Pakistan in 1995. A later plot, in 1998, to attack the US embassy in Albania was foiled.

The group is active outside Egypt, with suspected networks in Yemen, Pakistan, Afghanistan, Lebanon, Sudan and the UK.

al-Qaeda

The group was established in Afghanistan in the late 1980s by Osama bin Laden, in order to bring together Arabs who had fought against the Soviet invasion of the country for the Afghan resistance.

Subsequently, al-Qaeda developed a broadly anti-Western ideology and sought the overthrow of 'non-Islamic' regimes as well as the expulsion of Westerners and non-Muslims from Muslim countries. This was fuelled by bin Laden's outrage at the continued presence of US forces in Saudi Arabia - his country of birth - following the Gulf War.

The ideology resulted in a statement in February 1998 entitled The World Islamic Front for Jihad Against the Jews and crusders, which stated it was a duty for all Muslims to kill US citizens and the citizens of their allies. This was followed in August 1998 by the bombings of US embassies in Kenya and Tanzania, which left more than 300 people dead and 5,000 injured.

After al-Qaeda became the prime suspect for the attacks in East Africa, Bill Clinton, US president, authorised a cruise missile attack on al-Qaeda camps inside Afghanistan, but the impact was said to be negligible.

The group was also held responsible for the October 2000 suicide bomb attack on the USS Cole in the Yemeni port of Aden, which resulted in the deaths of 17 sailors. A number of other plots are also said to have been thwarted including one to assassinate Pope John Paul II on a visit to Manila.

The aftermath of the September 11 attacks has revealed the truly worldwide extent of the al-Qaeda network and its finances. It is said that it has cells in more than 50 countries and has also been effective in forging links with many other militant groups. The extensive network has enabled it to continue to pose a significant terrorist threat in spite of the removal of its base of operations in Afghanistan.

The US sees an assault on its finances as key to combating the group. In October 2001, the US Treasury attempted to freeze the assets of 21 groups and individuals linked to al-Qaeda. Among these were businesses and groups claiming to be charities.

Jaish-e-Mohammed (JEM) (Army of Mohammed) (Pakistan)

Only formed in February 2000, the Pakistan-based Jaish-e-Mohammed's profile increased after the group became the prime suspect in the murder of Dainel Pearl, the Wall Street Journal journalist. Prior to his death, e-mails were sent out to news agencies demanding the release of suspected al-Qaeda and Taliban prisoners being held at the US naval base in Guantanamo Bay, Cuba.

Three men arrested by Pakistani police in connection with the case are said to have acted on the orders of British-born Ahmed Omar Said Sheikh, a leading member of Jaish-e-Mohammed. Sheikh had spent five years in an Indian jail after taking three British backpackers hostage in 1994 and has been linked to the ringleader of the September 11 attacks, Mohammed Atta.

JEM is led by Maulana Masood Azhar, a former leader of the ultra-fundamentalist Harakat ul-Ansar (HUA), who was released from an Indian jail at the same time as Sheikh, in December 1999, in exchange for 155 hostages on a hijacked Indian Airlines flight. JEM's primary aim is to unite Kashmir with Pakistan. It is based in Peshawar and Muzaffarabad and has several hundred well-armed members in Pakistan, Azad Kashmir, Indian southern Kashmir and Doda.

al-Gama'a al-Islamiyya (Islamic Group, Egypt)

Egypt's largest militant group was established in the late 1970s with the aim of overthrowing the Egyptian government and replacing it with an Islamic state. The group engaged in attacks on security and other government officials, although from 1993 tourists became a significant target. al-Gama'a's most high-profile act was an attack at Luxor in 1997 which killed 58 foreign tourists. It also claimed responsibility for a failed attempt to assassinate Hosni Mubarak, the Egyptian president, in Ethiopia in 1995.

It is believed US interests may have become a specific target since Shaykh Umar Abd al-Rahman, the group's spiritual leader, was imprisoned in the US.

The group had announced a ceasefire in 1999 but key members, including al Rahman and Rifa'i Taha Musa, have since withdrawn their support.

In 1998 Taha Musa signed Osama bin Laden's fatwa calling for attacks against US civilians. In 2000 he appeared in a bin Laden video calling for retaliation against the US for the continued imprisonment of Abd al-Rahman.

Although operating mainly in Egypt al-Gama'a is said by the US State Department to have a presence in a number of other countries including Sudan, the UK, Afghanistan, Austria and the Yemen. The Egyptian government says support comes from Iran, Afghan militant groups and bin Laden.