The White House has strongly condemned a visit to Moscow by Syrian President Bashar al-Assad, BBC News reports. A spokesman criticized Russia for putting on a "red carpet welcome".

The Syrian leader's trip on Tuesday, October 20, came three weeks after Russia began air strikes in Syria against Islamic State militants and other forces.

It was Assad's first overseas trip since civil war broke out in Syria in 2011. The conflict has claimed more than a quarter of a million lives.

"We view the red carpet welcome for Assad, who has used chemical weapons against his own people, at odds with the stated goal by the Russians for a political transition in Syria," White House spokesman Eric Schultz told reporters.

A state department official said it was not surprised by the visit, but the main US concern was Russia's continued military support, which he said had emboldened the Assad government - something that would only serve to lengthen the civil war.

In the wake of Assad's surprise visit, President Putin spoke to a number of Middle Eastern leaders to brief them.

They included the leaders of Saudi Arabia and Turkey, which give support to Syrian rebels.

Putin also spoke to the Egyptian and Jordanian leaders, Russian news agencies said.

Turkish Prime Minister Ahmet Davutoglu said that after the visit "the Syrian government has no legitimacy left".