Syrian opposition activists have called for a simultaneous "Conference of National Salvation" to be held on Saturday in Damascus and Istanbul to look at ways to oust President Bashar al-Assad.

A statement said the conference will be held simultaneously in both cities "to draw up a road map that will bring the country out of despotism towards democracy and define the mechanism to overthrow the regime (as) sought by the (people of the) Syrian street."

More than one million protesters flooded Syrian streets on Friday seeking an end to President Bashar al-Assad's regime as security forces opened fire and killed at least 28, among them 23 in Damascus and its suburbs, and wounded nearly 100, an activist said.

Rights activist Abdul Karim Rihawi said the deaths included two in al-Qadam and four in Douma, both suburbs of the capital, in addition to three in the northwestern city of Idlib and two more in the southern town of Daraa.

Mystery shrouded the release of the kidnapped Estonians after high-ranking sources hinted of Syria’s involvement in setting free the seven cyclists as a good gesture to the European Union.

A high-ranking security source did not rule out that Syria helped release the hostages on Thursday after it was embarrassed by attacks by pro-regime supporters on the French and U.S. embassies in Damascus earlier in the week.

The International Atomic Energy Agency (IAEA) reported to U.N. Security Council members on Syria's suspected nuclear activities Thursday during a closed-door meeting.

"Council members were briefed by the IAEA, who provided the technical details that led to its conclusion of the violation by Syria of its nuclear non-proliferation obligations," said a French source.

Several southern towns in the Nabatiyeh, al-Zahrani and Tyre areas witnessed in the last few days an influx of more than 25 Syrian families fleeing the unrest in their country, Central News Agency reported Thursday.

Municipal sources in the South told the agency that some of the families were accommodated in shops due to overpopulation in the area during this time of year, while others had to reside in houses that are still under construction due to their inability to pay the rent of residential houses.

Syrian security forces killed two civilians when they opened fire on protesters in the eastern city of Deir al-Zour on Thursday, said Abdel Karim Rihawi of the Syrian League of Human Rights.

At least five more people were wounded in the shooting, Rihawi said.

Britain's Foreign Office summoned the Syrian ambassador on Wednesday over the attacks on the French and U.S. embassies in Damascus earlier this week, it said in a statement.

Sami Khiyami was called in over the raids on Monday by angry mobs apparently sparked by two Western envoys visiting the city of Hama, a flashpoint for protests against President Bashar Assad's regime, it said.

Syrian security forces killed four people as the West ratcheted up pressure for U.N. Security Council action against Damascus and France slammed China and Russia's "indecent" opposition to the move.

The four were killed Wednesday in the Jebel al-Zawiya region, where the army deployed two weeks ago to crush an anti-government revolt, Rami Abdel Rahman, head of the Syrian Observatory for Human Rights, told Agence France Presse by phone.

Arab League Secretary-General Nabil al-Arabi said Wednesday that Washington overstepped its bounds by saying Syrian President Bashar al-Assad had lost the legitimacy to lead his country.

Following talks with the Syrian president in Damascus, Arabi said Assad assured him that "Syria has entered a new era and is now moving on the road of a genuine reform."

An explosion hit a gas pipeline in northeastern Syria late Tuesday in the first attack on the country's energy infrastructure since protests erupted in March, a human rights activist said.

"The explosion hit the gas pipeline last night at 11 pm (20:00 GMT) in al-Tayyaneh northeast of the town of Mayadin," the director of the London-based Syrian Observatory for Human Rights, Rami Abdel Rahman, told Agence France Presse in Nicosia.