The sound of heavy gunfire was heard on Tuesday in the southwesten Damascus suburb of Mouadhamiya, which had seen intensifying demonstrations against President Bashar al-Assad's rule, a witness said.
"I tried to get in through Mouadhamiya's main entrance but there were scores of soldiers with rifles turning cars back," said the witness, who was in the area at 1:00 pm. (1000 GMT).
Unconfirmed reports by activists in the last two days said tanks had entered the large suburb. Mouadhamiya lies on the main road to the occupied Golan Heights, which overlook Damascus.
They said Internet and telephone lines have been cut to Mouadhamiya for the last two days, a common tactic used by security forces before storming demonstration hotspots.