At least 23 civilians were killed on February 5 as Syrian government forces launched air strikes against the rebel-held enclave of Eastern Ghouta near the capital Damascus, a monitor said.
Four children were among those killed, the Britain-based Syrian Observatory for Human Rights monitor said.
The observatory says at least 70 have been wounded.
The activist-run Ghouta Media Center also reported that 23 were killed.
An estimated 400,000 residents live in Eastern Ghouta, besieged by Syrian government forces.