Syrian Foreign Minister Walid Muallem has said he rejects "utterly and completely" that Syrian government forces used chemical weapons. He was speaking in Damascus after the US said there was "undeniable" proof of a chemical attack. Mr Muallem said UN weapons inspectors had been unable to go to a second site because they were stopped by rebels. The US and its allies are considering launching strikes on Syria in response to deadly attacks last week. Mr Muallem told a news conference that if a military act was carried out against Syria, the pretext of chemical weapons would be false, baseless and groundless. "They said the Syrian forces were the ones who carried out his attack. I deny this utterly and completely to [US Secretary of State John] Kerry," he said. "There is no country in the world that uses a weapon of ultimate destruction against its own people." The Syrian foreign minister also insisted the government was honouring all the pledges it made to the UN over access and protection for the inspectors.