Thousands of Tunisians angered by the increasing prominence of ultra-conservative Islamists in a country only recently freed from dictatorial rule took to the streets in protest Saturday.

An Agence France Presse correspondent estimated several thousand activists, professors, artists and other demonstrators flooded the streets of the nation's capital, including along Bourguiba Avenue, a well-known thoroughfare that became a center for dissent during protests that led to the ouster of dictator Zine el Abidine Ben Ali a year ago.

Syria said it was surprised by and regrets the Arab League's decision to suspend its observer mission to the unrest-swept country on Saturday.

"Syria is surprised by and regrets the decision taken by (Arab League chief Nabil) al-Arabi to suspend the observer mission after having decided (last week) to extend it for a month," state news agency SANA said on its website.

The Palestinian Islamist movement Hamas said on Saturday it does not plan to move its headquarters out of unrest-hit Syria.

"There is no change, and Hamas has not taken any decision to leave Syria, and we are still there," spokesman Fawzi Barhum told Agence France Presse.

Yemeni President Ali Abdullah Saleh, who is due to step down next month, landed in Britain on Saturday from Oman on his way to the United States for medical treatment, Yemeni and British officials said.

Saleh, who had mistakenly been reported to have left the Gulf sultanate earlier this week, arrived on Saturday afternoon at Stansted airport, just outside London, the Yemeni defense ministry's news website Sept.net said.

Two women employed by the office of Iraq's fugitive vice president Tareq al-Hashemi have been detained by security forces and may be at risk of torture, rights group Amnesty International said.

Hashemi, a Sunni, has been accused of running a death squad, a charge he denies. He is holed up in Iraq's autonomous Kurdistan region, which has so far declined to hand him over to the central government.

The opposition Syrian National Council on Saturday urged Syria's diaspora to protest outside Russian embassies against Moscow's opposition to a draft resolution on Syria at the U.N. Security Council.

"We call upon all Syrians abroad to show solidarity with our people inside the country and protest against the Russian position by holding sit-ins in front of the embassies of the (Syrian) regime, Russian embassies, and at U.N. centers tomorrow Sunday at 2:00 pm their local time," Samir Neshar, a member of the SNC's executive committee, said at a news conference in Istanbul.

The Arab League said on Saturday it was suspending its observer mission monitoring the deadly regime crackdown on dissent in Syria because of the upsurge in violence, a League official said.

"The decision to suspend the Arab League mission in Syria has been taken because of the upsurge in violence, and an official announcement will be made later," the official told Agene France Presse on condition of anonymity.

At least 15 Somali migrants were killed and 40 left missing after their boat capsized off the coast of Libya this week, the Somali ambassador to Tripoli told AFP on Saturday.

"Fifteen bodies, including one child and 12 women, were recovered off the coast of Misrata after their boat sank," ambassador Abdelghami Wais said, adding the bodies were found Wednesday on the shore of the western port city.

Traffic flowed through Cairo's Tahrir Square on Saturday after the end of a three-day sit-in to mark one year since the uprising that toppled President Hosni Mubarak, even as more protests were planned.

Tents were still pitched in the center of the square, where dozens of protesters gathered ahead of demonstrations to demand the ouster of the Supreme Council of the Armed Forces (SCAF) now ruling the country.

A high-ranking police officer, a soldier and four militants were killed in separate acts of violence in south Yemen, a security official and witnesses told Agence France Presse on Saturday.

The police official said Mubarak Barafaa, head of a criminal investigation unit, was cut down by machinegun fire late on Friday close to his house in Ghayl Ba Wazir, in the southeastern province of Hadramawt.