GETTY Vladimir Putin has heavily criticised Barack Obama's policy in Syria

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The US has backed groups against Syrian leader Bashar al-Assad with weapons and training. But Putin, who is supporting Assad in his fight against both the rebels and Islamic State, said today the backing is contrary to the United Nations charter. And in a scathing attack on the US support he said many of the weapons have just ended up with ISIS.

In my opinion, provision of military support to illegal structures runs counter to the principles of modern international law Putin

In an interview with American media ahead of Putin's meeting with US president Obama tomorrow, the Russian leader said: "In my opinion, provision of military support to illegal structures runs counter to the principles of modern international law and the United Nations Charter." US-Russian relations have slumped to a post-Cold War low over the Ukraine crisis, though the two sides share concerns about the threat posed by Islamic State, while disagreeing on the approach. Putin says Damascus should be included in international efforts to fight ISIS - a demand the America rejects, and he heavily criticised US plans to train up to 5,400 Syrian rebels to fight the terror organisation.

AP The Russian leader is due to meet Mr Obama tomorrow for talks about Ukraine and Syria

REUTERS Obama, pictured here with the Pope this week, has heavily criticised Assad's governance

He said: "It turns out that only 60 of these fighters have been properly trained, and as few as four or five people actually carry weapons. "The rest of them have deserted with the American weapons to join ISIS." The attack on US foreign policy comes as Russia develops its base in Syria by bringing 28 fighter aircraft to the war-torn country. That puts the Russian's in direct opposition to the US-led coalition, which wants Assad out. Last week, Putin said removing Assad would create a situation such as that seen in Libya where "all the state institutions deteriorate".

GETTY Syrian rebel forces have been backed by the US government

In yesterday's interview he defended his support for the Syrian leader. He said: "We have been providing assistance to legitimate government entities only. "As of today it has taken the form of weapons supplies to the Syrian government, personnel training and humanitarian aid to the Syrian people." Prime Minister David Cameron has sided with America and continually spoken of the need to remove Assad. Yesterday a spokesman for the PM said: "Our view is very clear, Isil and Assad are both the enemies of the Syrian people "The Prime Minister's view is still very clearly that in the endgame you need a different leader to build a peaceful and inclusive Syria."