Syrian government troops on Saturday closed all roads leading to the capital, Damascus, after opposition rebels attacked checkpoints in various parts of the city, activists said.
"Around 13 army checkpoints were attacked at the entrances of the capital, Damascus. This prompted the government troops to close areas, especially those leading to the eastern, western and southern suburbs of the capital," Haytham al-Abdullah, a Syrian activist based in Damascus, told dpa.
He added that government troops were mounting a widescale crackdown eight kilometers from Damascus.
Rebels are at pains to seize the city's airport and a main road leading to it in an attempt to cut supply lines to government troops, say activists.
Both sides have been fighting near the facility for more than a week.
Military commanders of several brigades from the rebel Free Syrian Army have agreed to unify their command. They selected a 30-member supreme military council, led by General Salim Idriss, in preparation for a decisive battle in Damascus, said activists.
News from Syria is hard to independently verify as authorities have barred most foreign media from the country since an uprising against the rule of President Bashar al-Assad started in March last year.
Meanwhile, the newly elected National Coalition of Syrian Revolutionary and Opposition Forces is to meet in Cairo on Saturday for talks on electing a prime minister and members of a transitional government in exile.
The United States and other Western powers have been pressuring the coalition, launched in Qatar last month, to show unity and coordinate with forces fighting to oust al-Assad's regime.