Syrian government forces have renewed their attacks in the capital, Damascus, killing at least 35 people in a campaign of shelling and artillery fire.

The Britain-based Syrian Observatory for Human Rights told VOA that Wednesday's deaths occurred in Kfar Souseh, Daraya and other southern districts where anti-government rebels operate.

Residents said the shelling and aerial bombardment were some of the fiercest since the army reasserted control over the opposition neighborhoods. They said rebels who left the city last month during a brutal army campaign had started to return.

In New York, United Nations political chief Jeffrey Feltman told the Security Council the U.N. views the rapidly deteriorating humanitarian situation in Syria “with growing alarm.” He said about 2.5 million people are in need of humanitarian assistance while the number of displaced people in Syria and the flow of refugees to neighboring countries is growing.

The U.N. emergency relief coordinator, Valerie Amos, who was in Syria last week, said U.N. agencies last month provided food for more than 820,000 people across Syria. She said the humanitarian situation there has worsened since a previous visit in March.

Meanwhile, British Prime Minister David Cameron and U.S. President Barack Obama warned Wednesday they would be forced to consider a new course of action if Syria threatens to use chemical weapons on rebel fighters.

The two leaders agreed during a telephone call that “the use – or threat – of chemical weapons was completely unacceptable and would force them to revisit their approach so far.”

The Russian newspaper Kommersant reported Wednesday that Moscow believes Syria has no intention of using its chemical weapons and is able to safeguard them.

Kommersant quoted a Russian Foreign Ministry official as saying a “confidential dialogue” with the Syrian government has convinced Russia that “the Syrian authorities do not intend to use these weapons and are capable of keeping them under control themselves.”