Russian president Vladimir Putin defended sending military equipment and personnel to support the regime of Syrian President Bashar al-Assad and called on the West to cooperate with Damascus to defeat Islamic State (Isis).

Speaking in Dushanbe, Tajikistan, where he was attending a meeting of a security alliance of former Soviet nations, he said Russia would continue to support Assad's government. "We give technical-military support to Damascus and will continue doing it," Putin said. "And we call on other countries to join us in this."

The Russian president said Assad was willing to work with Syria's "healthy" opposition to end the four-and-a-half-year civil war but said fighting IS was the priority and called for the formation of an international coalition to combat the jihadist group.

"Extremists from many countries of the world, including, unfortunately, European counties, Russia and the Commonwealth of Independent States (CIS) undertake ideological and military training in the ranks of Islamic State," said Putin. "And certainly we are worried that they could possibly return."

"Russia, as you know, has proposed to form a wide coalition to fight extremists without any delay. It [the coalition] should unite everyone who is ready and is already contributing to tackling terrorism."

Putin attacked critics of Moscow's support for the Assad regime. He said: "If Russia had not supported Syria, the situation in the country would be even worse than in Libya and the flow of refugees would be even greater."

The US has criticised Russia's military build up in Syria, and called for Greece and Bulgaria to block the passage of Russian transport planes. US Secretary of State John Kerry has claimed the Russian military presence could further escalate the conflict. The US insists Assad must leave office as part of any solution to the Syrian civil war.

Putin's spokesman, Dmitry Peskov, told reporters in Moscow on 15 September that dialogue between Moscow and Washington was essential for resolving the Syria crisis.

On 14 September, Pentagon spokesman Jeff Davis said the flow of personnel and equipment to the coastal city of Latakia suggested Russia was attempting to establish a forward operating base there. He expressed concern that Russian military manoeuvres could clash with US-led air strikes being conducted against IS positions in Syria.