UNITED NATIONS: Russian Foreign Minister Sergei Lavrov told the United Nations on Friday that US-Russian agreements aimed at ending the war in Syria must be salvaged as fighting raged on the ground.

Lavrov said there was “no alternative” to the Russian and US-led peace process and insisted that “now it is essential to prevent a disruption of these agreements.”

The foreign minister addressed the General Assembly after holding talks with US Secretary of State John Kerry on reviving a ceasefire in Syria that was shattered this week.

The Syrian army declared an end to the truce on Monday following a US-led coalition strike on Syrian soldiers near Deir Ezzor that Washington said was 'unintentional', following the air strike, the militant Islamic State attacked and seized a strategic mountain top.

The US-Russian ceasefire deal was further endangered by an attack on an aid convoy in Aleppo province on Monday the left 20 dead and destroyed 18 trucks.

The Russian foreign minister called for an “unbiased, impartial investigation of the incidents in Deir Ezzor and Aleppo that undermine these agreements.”

The Syrian crisis will not be resolved unless the United States and its allies rein in opposition rebels fighting alongside the Islamic State group and the Al-Qaeda-linked Nusra Front, Lavrov said.

“We will not be able to improve the humanitarian situation without the rooting out of the terrorist groups,” he said.

From the UN podium, Lavrov asserted that Russia's military intervention helped “prevent the collapse of statehood and disintegration of Syria” that would have plunged the Middle East further in chaos.

Kerry told reporters that there had been “a little bit of progress” during talks on the effort to put the ceasefire back on track.

Discussions have focussed on a US proposal to ground Syrian and Russian planes over designated areas, which Kerry said would restore “credibility” to the ceasefire plan.