Heavy clashes are taking place between Syrian government forces and insurgents east of Damascus amid at least a dozen air strikes, activists said.
The UK-based Syrian Observatory for Human Rights and Syrian activist Mazen al-Shami said the fighting was concentrated inside a military installation near the suburb of Harasta, where a government force has been trapped for a day.
The Observatory said the Syrian air force conducted at least a dozen air strikes on Harasta and nearby suburbs.
Mr al-Shami reported dozens of air strikes, saying the government had brought in reinforcements overnight and is trying to reach the trapped forces.
The Observatory said three days of violence in the suburbs of Damascus known as eastern Ghouta has killed 35 civilians, as well as 24 government troops and 29 insurgents.