According to CNN, at least 45 women and children were killed Sunday in Homs.
The massacre took place in the Karm al Zaytoun neighborhood after peace talks between the Syrian regime and a U.N. special envoy failed to bring about a ceasefire, according to the article.
The women and children were stabbed and burned to death, activists said. Women and girls were sexually assaulted and shot, according to the London-based Syrian Network for Human Rights.
Another 108 people were killed nationwide on Sunday, activists said.
Tuesday will be an official day of mourning across Syria, the Local Coordination Committees of Syria said.