Human Rights Watch said Saturday attacks near Aleppo and Homs in the past two weeks killed 11 people -- most of them women and children -- and injured 27, CNN reported.
"Syria is expanding its relentless use of cluster munitions, a banned weapon, and civilians are paying the price with their lives and limbs," said Steve Goose, director of the group's arms division.
Cluster bombs break up into hundreds of bomblets.
"The initial toll is only the beginning because cluster munitions often leave unexploded bomblets that kill and maim long afterward," Goose said.
The rights group said it has discovered the government has used at least 156 cluster bombs in 119 places across the country since August.
Syria, like the United States, has not signed the international convention banning cluster bombs.