BEIRUT — Syrian activists said airstrikes targeting the Islamic State group’s de factor capital of Raqqa on Thursday killed at least 20 civilians in a new round of bombardment that came as Turkey called on Russia to carry out joint operations against IS.

The offer by Turkish Foreign Minister Mevlut Cavusoglu followed a meeting between the Russian and Turkish leaders in which they agreed to mend ties.

Cavusoglu also announced that his country will resume its airstrikes against IS targets in Syria, months after they were suspended amid a major row with Moscow. He said in an interview with Turkey’s private NTV television that Ankara “will again, in an active manner, with its planes take part in operations” against IS targets.

Turkey had temporarily suspended its limited participation in the airstrikes campaign by the U.S.-led coalition, following soured relations with Moscow after Turkish air force jets downed a Russian warplane on the Syrian border in November. Russia had retaliated by deploying long-range air defense missile systems to its base in Syria, 50 kilometers (30 miles) south of the border with Turkey and imposing an array of economic sanctions.

“On the issue of Daesh, we have made a call to Russia. We said we have a common enemy which we can struggle against together,” he said. Daesh is an Arabic language acronym for the Islamic State group.

Also Thursday, Syrian activists reported that at least 20 civilians were killed in airstrikes on Raqqa, the IS de facto capital in northern Syria.

The local activist group Raqqa is Being Slaughtered Silently said the strikes also cut the city’s water supply. The Britain-based Syrian Observatory for Human Rights reported the airstrikes, saying that 24 civilians were killed, along with six others whose affiliation or identities could not yet be confirmed.

Both groups said the strikes were launched by Russian jets, though it was not clear how they made the determination.

Meanwhile, there was no letup in the embattled northern Syrian city of Aleppo, where Turkey and Russia are supporting opposing sides of the conflict and where residents and activists reported a chlorine gas attack.