Syrian leader Bashar al Assad says he is committed to destroying his stockpile of chemical arms - but warned it would take a year to do so.

In an interview with Fox News, Mr Assad said he was committed to getting rid of the arsenal but conceded it would cost at least €715 million.

He also insisted that his decision to destroy the weapons was not forced upon him by the threat of US strikes.

Mr Assad said a UN report that found "clear and convincing evidence" of a sarin nerve gas attack in Syria last month is "unrealistic", and denied responsibility for it.

During the interview with the US crew at the presidential palace in Damascus, Mr Assad said destroying the weapons was "a very complicated operation, technically".

"And it needs a lot of money, about a billion," he continued.

"So it depends, you have to ask the experts what they mean by quickly. It has a certain schedule.

"It needs a year, or maybe a little bit more."

Mr Assad also used the one-hour interview to criticise the American stance in the Syrian crisis.

He said that, unlike Russia, Washington had tried to get involved in Syria's leadership and governance.

Mr Assad's comments came after a senior Russian diplomat said Damascus would stick to its commitment to eliminate its chemical weapons by mid-2014.

After talks in Syria, Deputy Foreign Minister Sergei Ryabkov said Mr Assad was "very serious" about the disarmament plan.

Mr Ryabkov also said Syrian officials had shown him "material evidence" implicating rebels in the sarin attack.

The Russian diplomat criticised the UN for being "one-sided" in its recent report on the attack.