Syrian government forces battled rebels in Damascus Thursday, as the government of President Bashar al-Assad fights to drive out opposition forces from the capital city.

Activists reported fighting in several neighborhoods, including a campaign of shelling and house-to-house raids in Daraya, on the southwest edge of the city.

The Britain-based Syrian Observatory for Human Rights told VOA at least 35 people were killed in Damascus on Wednesday. Residents said the fighting was the fiercest since the army recently reasserted control of opposition-held neighborhoods there.

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.”