Russia's ambassador to the United Nations said on Monday that Eastern Ukraine had been on the brink of a new "Ukrainian military adventure" that Russia could not allow, and vowed it would not let a 'new bloodbath' happen in the region.

Speaking at an emergency meeting of the UN Security Council, the Russian ambassador, Vassily Nebenzia, also warned Western powers to 'think twice' and not worsen the situation in Ukraine.

Russian President Vladimir Putin ordered the deployment of troops to two breakaway regions in eastern Ukraine after recognising them as independent on Monday, accelerating a crisis the West fears could unleash a major war.

Earlier on Tuesday, the United Nations regretted Russia's order to deploy troops into eastern Ukraine on a reported 'peacekeeping mission', the body's political affairs chief told an emergency Security Council meeting on Monday, warning that the risk of 'major conflict' was real and needed to be prevented.

Speaking at the last minute meeting over Ukraine, UN political affairs chief Rosemary DiCarlo reiterated that the United Nations was committed to the sovereignty, independence and territorial integrity of Ukraine, within internationally recognised borders.

Meanwhile, Linda Thomas-Greenfield, US ambassador to the United Nations said on Monday that Russia's order to deploy 'peacekeepers' in eastern Ukraine is 'nonsense', adding that Moscow's recognition of the breakaway eastern regions were part of its attempt to create a pretext for a further invasion of Ukraine.

Speaking at an emergency UN Security Council meeting on Ukraine, Greenfield said the consequences of Russia's actions will be dire across Ukraine, Europe and worldwide and that the humanitarian toll will expand significantly if Moscow invaded further.