9 February 2011 Last updated at
Profile: Egypt's Muslim Brotherhood
The Ikhwan's most frequently used slogan is: "Islam is the solution"
The Muslim Brotherhood, or al-Ikhwan al-Muslimun, is Egypt's oldest and largest Islamist organisation.
Founded by Hassan al-Banna in the 1920s, the group has influenced Islamist movements around the world with its model of political activism combined with Islamic charity work.
The movement initially aimed simply to spread Islamic morals and good works, but soon became involved in politics, particularly the fight to rid Egypt of British colonial control and cleanse it of all Western influence.
Today, though officially banned and subject to frequent repression, the Ikhwan lead public opposition to the ruling National Democratic Party of President Hosni Mubarak, who has been in power since 1981.
While the Ikhwan say that they support democratic principles, one of their stated aims is to create a state ruled by Islamic law, or Sharia. Their most famous slogan, used worldwide, is: "Islam is the solution".
After Banna launched the Muslim Brotherhood in 1928, branches were set up throughout the country - each running a mosque, a school and a sporting club - and its membership grew rapidly.
Hassan al-Banna was assassinated by an unknown gunman in 1948
By the late 1940s, the group is believed to have had as many as two million followers in Egypt, and its ideas had spread across the Arab world.
At the same time, Banna created a paramilitary wing, the Special Apparatus, whose operatives joined the fight against British rule and engaged in a campaign of bombings and assassinations.
The Egyptian government dissolved the group in late 1948 for attacking British and Jewish interests. Soon afterwards, the group was accused of assassinating Prime Minister Mahmoud al-Nuqrashi.
Banna denounced the killing, but he was subsequently shot dead by an unknown gunman - believed to have been a member of the security forces.
In 1952, colonial rule came to an end following a military coup d'etat led by a group of young officers calling themselves the Free Officers.
The Ikhwan played a supporting role - Anwar al-Sadat, who became president in 1970, was once the Free Officers' liaison with them - and initially co-operated with the new government, but relations soon soured.
Egypt's oldest and largest Islamist organisation
Founded by Hassan al-Banna in 1928
Has influenced Islamist movements worldwide
Mixes political activism with charity work
Banned from open political activity
Rejects use of violence and supports democratic principles
Wants to create a state governed by Islamic law
Slogan: "Islam is the Solution"
After a failed attempt to assassinate President Gamal Abdul Nasser in 1954, the Ikhwan were blamed, banned, and thousands of members imprisoned and tortured. The group continued, however, to grow underground.
This clash with the authorities prompted an important shift in the ideology of the Ikhwan, evident in the writing of one prominent member, Sayyid Qutb.
Qutb's work advocated the use of jihad (struggle) against jahili (ignorant) societies, both Western and so-called Islamic ones, which he argued were in need of radical transformation.
His writings - particularly the 1964 work Milestones - inspired the founders of many radical Islamist groups, including Islamic Jihad and al-Qaeda.
In 1965, the government again cracked down on the Ikhwan, executing Sayyid Qutb in 1966 and making him a martyr throughout the region.
During the 1980s the Ikhwan attempted to rejoin the political mainstream.
The Muslim Brotherhood is officially banned and subject to frequent repression
Successive leaders formed alliances with the Wafd party in 1984, and with the Labour and Liberal parties in 1987, becoming the main opposition force in Egypt. In 2000, the Ikhwan won 17 seats in the People's Assembly.
Five years later, the group achieved its best election result to date, with independent candidates allied to it winning 20% of the seats.
The result shocked President Mubarak. The government subsequently launched a crackdown on the Ikhwan, detaining hundreds of members, and instituted a number of legal "reforms" to counter their resurgence.
The constitution was rewritten to stipulate that "political activity or political parties shall not be based on any religious background or foundation"; independent candidates were banned from running for president; and anti-terrorism legislation was introduced that gave the security forces sweeping powers to detain suspects and restrict public gatherings.
Leaders of President Mubarak's ruling National Democratic Party (NDP) also worked hard to reduce the likelihood of further opposition gains in the November 2010 parliamentary elections.
But their efforts backfired somewhat - the failure of candidates allied to the Ikhwan to win a single seat in the first round was accompanied by allegations of widespread fraud.
The Muslim Brotherhood boycotted the second round of the November 2010 elections
The group subsequently joined other opposition parties in announcing a boycott of the second round, and the NDP was left in the embarrassing situation of taking more than 80% of the seats in the People's Assembly.
The continued repression of the opposition was one of the main triggers for the mass anti-government protests by thousands of Egyptians in late January 2011, which saw the NDP's headquarters in Cairo set on fire.
The Ikhwan were blamed for fomenting the unrest, but its deputy general guide, Mahmoud Izzat, insisted it was a popular uprising.
"We are part of the people. The people are demanding the basics - mainly the necessities of life - and they have the right to do so. The people also demand their freedom and the dissolution of the fake parliament," he told al-Jazeera TV.
"The youths want the demonstrations to be peaceful but the regime uses excessive violence against the youths, such as rubber bullets."
We want a civil state, based on Islamic principles - a democratic state, with a parliamentary system, with freedom to form parties, press freedom, and an independent and fair judiciary”
Muslim Brotherhood Guidance Bureau
Though many members of the Ikhwan joined the protests, they maintained a low profile. The group's traditional slogans were not seen in Tahrir Square.
But as the protests grew and the government began to offer concessions, including a promise by Mr Mubarak not to seek re-election in September 2011, Egypt's largest opposition force took a more assertive role.
At the beginning of February 2011, the Ikhwan's leadership issued a statement saying: "We demand that this regime is overthrown, and we demand the formation of a national unity government for all the factions."
They also attended an unprecedented meeting between the government and opposition. The talks degenerated into a war of words, with the Ikhwan rejecting Vice-President Omar Suleiman's assertion that consensus had been reached, but the invitation was tacit recognition of their wide support and importance to the protest movement.
'Religious guidance council'
The Ikhwan's increased prominence also triggered renewed debate about what they would do if they became the dominant political force in Egypt.
Many critics, particularly in the US, pointed to a draft political platform published by the group in 2007, which called for a council of religious scholars to be set up to approve all laws passed by Egypt's civilian institutions. The platform also stated that Christians or women could not become president or prime minister.
Adhering more to Islamic Sharia law has widespread popular appeal among Egyptians
Moderates within the Ikhwan openly disagreed with the manifesto at the time, saying they wanted only an Islamic frame of reference for legislation, while conservatives noted that Article 2 of the constitution stated: "Islam is the religion of the state and the principles of the Islamic Sharia are the main source of legislation".
It is clear, however, that the Ikhwan's leaders are deeply committed to increasing the role of Islam in Egyptian public life; that adhering more to Sharia has widespread popular appeal; and that many of the group's supporters expect it to place Sharia at the centre of its political agenda.
Despite such aims, a senior member of the Ikhwan's Guidance Bureau, Issam al-Aryan, has told the BBC that the movement would not put forward its own candidate in any forthcoming presidential election, and that instead it wanted the opposition to nominate a consensus candidate.
"We want a civil state, based on Islamic principles. A democratic state, with a parliamentary system, with freedom to form parties, press freedom, and an independent and fair judiciary," he added.
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