WASHINGTON -- Syrian President Bashar Assad said a United Nations report finding "clear and convincing evidence" that sarin nerve gas was used in Syria painted an "unrealistic" account, and he denied his government orchestrated the attack.

In an interview with Fox News Channel conducted in the Syrian capital of Damascus and aired Wednesday, Assad said terrorists were to blame for the chemical attack, which the U.S. says killed more than 1,400 people, including hundreds of children. He said evidence that terrorist groups have used sarin gas has been turned over to Russia and that Russia, through one of its satellites, has evidence that the rockets in the Aug. 21 attack were launched from another area.

While the U.S. report did not lay blame, many experts interpreting the report said all indications were that the attack was conducted by Assad forces. U.S., Britain and France jumped on evidence in the report -- especially the type of rockets, the composition of the sarin agent, and trajectory of the missiles -- to declare that Assad's government was responsible.

"The whole story doesn't even hold together," Assad said. "It's not realistic. ... We didn't use any chemical weapons in Ghouta," a Damascus suburb.

The interview was conducted Tuesday by former Democratic Rep. Dennis Kucinich, a Fox News contributor, and Fox News Channel Senior Correspondent Greg Palkot.

Assad said his government would abide by an agreement reached with U.S. and Russian officials to give up his chemical weapons. He says he has received estimates that destroying the stockpiles would cost $1 billion and would take roughly a year.

"We didn't say that we are joining partially. ... We joined fully. We sent the letter. We sent the document. And we are committed to the full requirement of this agreement."

He said Syria was ready to talk to experts about the technical aspects of what he said would be a complicated task. He said Syria was ready to provide a list of weapons and provide experts access to the sites.

"We can do it tomorrow," he said.

"It's not about will," Assad added. "It's about technique."

While he said the Aug. 21 attack was "despicable" and "a crime," he argued that no one had verified the credibility of videos or pictures of the victims.

"You cannot build a report on videos," he said. He later added: "There's a lot of forgery on the Internet."

He contended that opposition forces, which have been joined by extremist jihadists, could have gained access to sarin.

"Sarin gas is called kitchen gas," he said. "You know why? Because anybody can make sarin in his house. Any rebel can make sarin. Second, we know that all the rebels are supported by governments. So any government that would have such chemical can hand it over."

Assad said the balance of opposition forces has shifted during the more than two-year conflict, and he alleged that 80 to 90 per cent were members of al-Qaida or its affiliates.

"At the very beginning, the jihadists were the minority. At the end of 2012 and during this year, they became the majority with the flow of tens of thousands from additional countries," he said adding that they were being financed by individuals who shared their extremist ideologies.

Assad said he had never talked with President Barack Obama. Asked if he wanted to, Assad said it would depend on the content of the conversation.

"It's not a chat," he said.

He said his message to Obama would be to "follow the common sense" of the American people.

Americans have been lukewarm about supporting any military strike on Syria for fear that the U.S. would be embroiled in war.