Syrian President Bashar Assad has blamed Europe's refugee crisis on Western support for "terrorists", as people fleeing his country's civil war stream towards the European Union.

In his first public comments on the mass migration, broadcast on Wednesday, Assad said Europe could expect more refugees.

Countries including the United States, Turkey and Saudi Arabia want to see Assad gone from power and have supported the opposition to his rule during the four-year-old war, including some of the armed groups fighting him.

Assad said Turkish support had been crucial to the growth of two of the biggest insurgent groups in Syria, Islamic State and the al-Qaeda-linked Nusra Front, and aerial bombing by a U.S.-led coalition had failed to stop Islamic State. Turkey denies the accusation.

The Syrian president dismissed Western suggestions that his government's actions in the war had fuelled the spread of such groups.

"As long as they follow this propaganda, they will have more refugees," Assad said in an interview with Russian media. "If you are worried about them, stop supporting terrorists."

The Syrian government describes all the armed groups fighting it as terrorists. The insurgents in Syria range from the hardline Islamic State group to nationalists viewed as moderate by the West.

Russian support

Assad has been buoyed in recent weeks by signs of increased military support from his ally Russia. In his comments he made no mention of reports of Russian military activity in Syria.

The White House said on Tuesday it wanted to see Russia engage constructively with the international coalition fighting Islamic State, rather than build up its own military presence.

The Associated Press has reported that U.S. Secretary of State John Kerry placed his third phone call in 10 days to Russian Foreign Minister Sergey Lavrov, seeking clarity about Moscow's moves.

Moscow says the Syrian government should be part of a broad coalition to fight Islamic State.

Assad said there was no co-ordination between his government and the United States, even indirectly, apparently backing away from comments earlier this year suggesting there had been some contact.

"There's not a single co-ordination or contact between the Syrian government and the United States government or between the Syrian army and the U.S. army ... Not even any third party including the Iraqis," he said.

He played down proposals for a peace initiative that Assad ally Iran has said it presented to Syrian officials.

"There is currently no Iranian initiative, but rather there are ideas, or principles, for an Iranian initiative which are based principally on the subject of Syria's sovereignty ... and are based on fighting terrorism," Assad said.