Syrian President Bashar al-Assad has said he is committed to a plan to destroy his country's chemical weapons but warned it could take about a year.
Speaking to Fox News TV, Mr Assad again denied claims that his forces were responsible for a deadly chemical attack near Damascus on 21 August.
The Syria disarmament plan was unveiled by the US and Russia last weekend.
The West wants the deal enshrined in a UN resolution backed by the threat of military force, but Russia objects.
Damascus - backed by Moscow - has insisted that rebel forces carried out last month's attack in the Ghouta area.
In a separate development, fierce fighting has been reported between two rebel groups.
Activists said the fighting began when jihadists from the al-Qaeda-linked group, the Islamic State of Iraq, and fighters from the Western-backed Free Syrian Army clashed in the town of Azaz, near the Turkish border.
This is believed to be one of the biggest confrontations so far between the jihadists and the FSA.
'Listen to your people'
Referring to the issue of destroying Syria's stockpiles of chemical weapons, Mr Assad said it was "a very complicated operation, technically".
"And it needs a lot of money, some estimates (say) about a billion.
"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."
And when asked whether he would be willing to hand over chemical to the US, President Assad said: "It needs about one billion. It is very detrimental to the environment. If the American administration is ready to pay this money and take the responsibility of bringing toxic materials to the United States, why don't they do it?"
Mr Assad also used the one-hour interview recorded in Damascus to criticise the American stance in the Syrian crisis.
Unlike the Russians, he said, Washington had tried to get involved in Syria's leadership and governance.
He stressed that if there was mutual respect, there would not be any problems.
"Listen to your people. Follow the common sense of your people," he said, in an apparent reference to US President Barack Obama.
Mr Assad's comments come shortly after a senior Russian diplomat said Damascus would fulfil its commitment to eliminate its chemical weapons by mid-2014.
After talks in Syria, Deputy Foreign Minister Sergei Ryabkov said President Assad was "very serious" about the disarmament plan.
Mr Ryabkov also said that Syrian officials had handed him "material evidence" that showed the rebels were involved in the sarin attack last month, contradicting claims by the US that the regime was responsible.
And the Russian diplomat criticised the United Nations for being "one-sided" in its recent report on the attack - a claim the UN denied.
The report - prepared for UN weapons experts after a visit to Syria - did not apportion blame for the 21 August attack.
More than 100,000 people have been killed since Syria's civil war began in early 2011, according to the UN.
Millions have fled the country and millions more have been left homeless.