Troops loyal to Syrian president Bashar al-Assad and Russian forces on Tuesday launched a new assault on rebel groups in the city of Aleppo. Britain-based Syrian Observatory for Human Rights said that at least five civilians killed in airstrikes carried out in the city, the first of its kind since October 18, AFP reported.

“Regime aircraft launched strikes and dropped barrel bombs on a number of neighbourhoods in the east of Aleppo,” said RA Rahman, the director of the group, The Guardian reported. Russia also launched strikes from its aircraft carrier, the Admiral Kuznetsov, according to BBC. The United States condemned the renewed campaign and said that airstrikes on civilian targets constituted a violation of international law.

United Nations members also condemned the attacks. However, Moscow denied it was conducting airstrikes in the city and said it was targeting militant groups in other parts of Syria. The new assault on the city comes after a three-week pause in airstrikes on humanitarian grounds.

Fighting between forces loyal to Assad and rebel groups intensified after a ceasefire deal broke down in September when an aid convoy was bombed in Aleppo. More than 3,00,000 people have died in the six-year-long civil war and nearly half the country’s population has been forced to flee since it began.