Pope Francis has renewed his appeal for peace in Syria while addressing pilgrims and tourists in St. Peter's Square for his weekly Wednesday General Audience as the United States and Russian said they would resume peace negotiations at the weekend.

"I want to emphasize and reiterate my solidarity with all victims of inhuman conflict in Syria," said Francis.

"It is with a sense of urgency that I renew my appeal, begging, with all my strength, those responsible, that steps be taken toward an immediate ceasefire, one imposed and respected at least for the time necessary to allow the evacuation of civilians, especially children, who are still trapped under cruel bombardment."

Russian-led airstrikes resumed this week, concentrating on targets within the besieged city of Aleppo, once Syria's biggest.

At least 25 people are reported to have died, including children and 45 were wounded.

The bombardments follow a temporary lull called by the Syrian government, in part to allow civilians to leave rebel-held areas in the east of the city.

The mayor of Aleppo, Brita Haj Hassan, lambasted the international community for failing to halt government and Russian airstrikes on the city, Sky News reports.

His criticism followed a U.N. warning that Aleppo could be completely destroyed before Christmas if the onslaught continues.

Hassan told Sky News: "We consider the international community as partners in these war crimes...There is a holocaust going on in Aleppo right now. Aleppo is burning and the international community is just watching and doing nothing."

The U.S and Russia announced that they will resume talks on Syria, which broke down earlier this month, the BBC reported.

The United States broke off negotiations with Russia nine days ago with extreme tension arsing over a failure to secure a truce.

Russia's Foreign Minister Sergei Lavrov is to meet his U.S, counterpart John Kerry and other key regional powers probably in Lausanne Switzerland on Oct. 16.

The announcement followed two days of renewed air strikes on Aleppo in which at least 75 people were killed.

The U.S. State Department said Kerry will discuss a "multilateral approach" to ending the crisis, "including a sustained cessation of violence and the resumption of humanitarian aid deliveries."

Key regional powers, Saudi Arabia, Turkey and Iran are expected to attend the talks in Lausanne.