The Syrian leader Bashar al-Assad has made a surprise visit to Moscow to discuss the continuation of Russian airstirkes with President Vladimir Putin.

At the talks, President Assad expressed "enormous" gratitude for the Kremlin's help and said its military intervention in his country had prevented a "tragic scenario".

It is the first known trip abroad taken by the Syrian president since his country's civil war began in 2011 - more than 250,000 people are reported to have died since then.

The Kremlin made details of the talk public on Wednesday, although the two are said to have met on Tuesday.

A statement posted on the Syrian presidency's official Facebook page said the pair had discussed the continuation of the military operations in Syria.

The statement added that the aim of the military operation was to eradicate terrorism so that a political solution could be found.

The post included a photo of Mr Assad with a wide smile shaking hands with the Russian president while Russian television showed footage of Mr Putin and Russia's foreign and defence ministers meeting Mr Assad and his adviser.

Mr Putin thanked his Syrian counterpart "accepting our invitation and coming to Moscow despite a tragic situation in your country" and said he would work closely with other world powers to find a peaceful solution to the conflict.

Mr Assad has now returned to Damascus.

The meeting came three weeks after Russia began carrying out air strikes against Islamist militants in Syria.

A week after Russia launched its air strikes, Syrian ground troops, helped by allied fighters from Iran and Lebanon's Hezbollah, pushed their way into central and northern Syria to try to drive rebel and militant groups out.

So far, Syrian forces are reported to have seized some villages but have not yet had any strategic victory.