At least 46 people, including 28 civilians, were killed and about 100 others were wounded in twin car bomb blasts in the central Syrian city of Homs Sunday, according to the Britain-based Syrian Observatory for Human Rights (SOHR). The incident, which took place in al-Zahraa neighborhood in Homs, was one of the deadliest such attacks in the city since the civil war started in 2011.

State-run media quoted the governor of Homs as saying at least 25 people are dead, Reuters reported. Sunday’s attacks come a day after the Syrian government, backed by Russian fighter jets, advanced against the Islamic State group, also known as ISIS, in eastern Aleppo and recaptured 18 villages Saturday. No one has yet claimed responsibility for the attack.

Pro-government television channels showed charred corpses buried among rubble, with burnt down shop fronts and debris littering al-Zahraa, the city’s center, according to Reuters. This is the second time the neighborhood has been attacked in less than a month.

SOHR Director Rami Abdulrahman said the attack was the second most deadly of its kind in Homs since 2011, and the deadliest for almost a year and a half, Reuters reported.

A ceasefire brokered earlier this month was almost immediately broken as the Syrian government along with the Russian air force intensified attacks against ISIS posts in Aleppo province. Russia and the U.S. are jointly chairing a United Nations meeting in Geneva aimed at trying to secure a cessation of hostilities in Syria.

On Saturday, the U.S.-backed Syrian opposition forces reportedly agreed to a two-to-three-week truce on condition that Russia stopped its airstrikes and access for humanitarian aid for civilians allowed across the country.