A Russian news presenter, dubbed the “Kremlin’s chief propagandist”, has warned the United States any “impudent behaviour” towards Moscow could have “nuclear” implications.

Dmitry Kiselyov, who was appointed by Vladimir Putin to head the country’s government-owned news agency, made the warning on Monday night’s edition of his flagship current affairs programme Vesti Nedeli (News of the Week).

Relations between the two countries hit a new low on Friday after Washington accused Moscow of war crimes following a sustained bombardment of the besieged Syrian city Aleppo, where at least 250,000 people are still living in the rebel-held east of the city.

John Kerry says Russia and Syria should be probed for war crimes

On Saturday, Russia vetoed a motion put to the UN Security Council demanding an immediate end to the bombing campaign in Aleppo. A rival motion proposed by Russia was also rejected at the meeting calling for a fresh ceasefire but did not explicitly mention the bombing.

In pictures: Russian air strikes in Syria Show all 19 1 /19 In pictures: Russian air strikes in Syria In pictures: Russian air strikes in Syria Syrian boys cry following Russian air strikes on the rebel-held Fardous neighbourhood of the northern embattled Syrian city of Aleppo Getty In pictures: Russian air strikes in Syria Russian defense ministry spokesman Major General Igor Konashenkov speaks to the media in Moscow, Russia. Konashenkov strongly warned the United States against striking Syrian government forces and issued a thinly-veiled threat to use Russian air defense assets to protect them AP In pictures: Russian air strikes in Syria Syrians wait to receive treatment at a hospital following Russian air strikes on the rebel-held Fardous neighbourhood of the northern embattled Syrian city of Alepp Getty In pictures: Russian air strikes in Syria Russian Deputy Defense Minister Anatoly Antonov speaks at a briefing in the Defense Ministry in Moscow, Russia. Antonov said the Russian air strikes in Syria have killed about 35,000 militants, including about 2,700 residents of Russia AP In pictures: Russian air strikes in Syria Jameel Mustafa Habboush, receives oxygen from civil defence volunteers, known as the white helmets, as they rescue him from under the rubble of a building following Russian air strikes on the rebel-held Fardous neighbourhood of the northern embattled Syrian city of Aleppo Getty In pictures: Russian air strikes in Syria Civil defence members rest amidst rubble in a site hit by what activists said were airstrikes carried out by the Russian air force in the town of Douma, eastern Ghouta in Damascus, Syria Reuters In pictures: Russian air strikes in Syria A girl carrying a baby inspects damage in a site hit by what activists said were airstrikes carried out by the Russian air force in the town of Douma, eastern Ghouta in Damascus, Syria Reuters In pictures: Russian air strikes in Syria Civilians and civil defence members look for survivors at a site damaged after Russian air strikes on the Syrian rebel-held city of Idlib, Syria Reuters In pictures: Russian air strikes in Syria Civilians and civil defence members carry an injured woman on a stretcher at a site damaged after Russian air strikes on the Syrian rebel-held city of Idlib, Syria Reuters In pictures: Russian air strikes in Syria Volunteers from Syria Civil Defence, also known as the White Helmets, help civilians after Russia carried out its first airstrikes in Syria In pictures: Russian air strikes in Syria The aftermath of Russian airstrike in Talbiseh, Syria In pictures: Russian air strikes in Syria Smoke billows from buildings in Talbiseh, in Homs province, western Syria, after airstrikes by Russian warplanes AP In pictures: Russian air strikes in Syria Russian Air Forces carry out an air strike in the ISIS controlled Al-Raqqah Governorate. Russia's KAB-500s bombs completely destroy the Liwa al-Haqq command unit In pictures: Russian air strikes in Syria Caspian Flotilla of the Russian Navy firing Kalibr cruise missiles against remote Isis targets in Syria Â© TASS/ITAR-TASS Photo/Corbis In pictures: Russian air strikes in Syria Russia claimed it hit eight Isis targets, including a "terrorist HQ and co-ordination centre" that was completely destroyed In pictures: Russian air strikes in Syria A video grab taken from the footage made available on the Russian Defence Ministry's official website, purporting to show an airstrike in Syria In pictures: Russian air strikes in Syria A release from the Russian defence ministry purportedly showing targets in Syria being hit In pictures: Russian air strikes in Syria Russia launched air strikes in war-torn Syria, its first military engagement outside the former Soviet Union since the occupation of Afghanistan in 1979. Russian warplanes carried out strikes in three Syrian provinces along with regime aircraft as Putin seeks to steal US President Barack Obama's thunder by pushing a rival plan to defeat Isis militants in Syria In pictures: Russian air strikes in Syria Caspian Flotilla of the Russian Navy firing Kalibr cruise missiles against remote Isis targets in Syria, a thousand kilometres away. The targets include ammunition factories, ammunition and fuel depots, command centres, and training camps Â© TASS/ITAR-TASS Photo/Corbis

Mr Kiselyov said there had been a “radical change” in the relationship between Russia and the US in recent weeks, the BBC reports.

“The loud talk in Washington of a ‘Plan B’ for Syria. Everyone understands what this means: direct military force in Syria,” he said.

During Monday’s programme a Russian defence ministry spokesman also warned US bombers not to target the Syrian army. “We’ll shoot them down,” commented Mr Kiselyov.

Loading....

Mr Kiselyov is a key part of Russia’s media operations and has been described as a “militant anti-Westerner” by Russian media and the county’s “chief propagandist”. He is also subject to Western sanctions.

In the past he has boasted that Russia was the only single country “genuinely capable of turning the USA into radioactive ash” and claimed last year: "In Syria, America stands on the side of the terrorist caliphate”.

His most recent comments come as Russia bolsters its military presence in the Mediterranean and Baltic regions.

Russia recently deployed the S-300 anti-aircraft missiles system to Syria and sent three war ships armed with Malakhit cruise missiles from the Black Sea Fleet to the Mediterranean.

On Saturday, Moscow confirmed it has started moving nuclear-capable Iskander-M missiles into the Kaliningrad, an act Poland said it considers a matter of the “highest concern”.

The German foreign minister claimed that mounting tensions between the US and Russia have led to a global political situation which is “more dangerous” than the Cold War.

Writing for German newspaper Bild, Frank-Walter Steinmeir wrote: “It's a fallacy to think that this is like the Cold War. The current times are different and more dangerous”.

Western powers and Russia clash at UN over Syria

Former cabinet minister Andrew Mitchell compared Russia’s actions in the Syrian conflict to that of the Nazis before World War II, saying Russia has “shredded” international law by providing military support for Syrian President Bashar al-Assad’s bombing campaign of rebel neighbourhoods.