'Russian troops deployed' in Ukraine - Petro Poroshenko Published duration 28 August 2014 Related Topics Ukraine conflict

media caption Ukrainian officials have expressed a great deal of worry and concern, as David Stern reports

Ukraine's President Petro Poroshenko has accused Russia of deploying its troops in the east of his country.

His remarks came as pro-Russian rebels opened a new front in the south by seizing the coastal town of Novoazovsk.

Nato says it has detected a significant increase of Russian arms being supplied to the rebels over the past two weeks.

Russia has denied that its forces have crossed Ukraine's border. At least 2,119 people have been killed in four months of fighting.

The United Nations Security Council is to hold an emergency meeting in New York on Thursday at 18:00 GMT to discuss the crisis.

Nato Brigadier General Niko Tak told the BBC that there had been a "significant escalation in the level and sophistication of Russia's military interference in Ukraine" over the past two weeks.

image copyright Reuters image caption This satellite image provided by the Supreme Headquarters Allied Powers Europe shows what Nato identifies as Russian self-propelled artillery in Ukraine

"[Nato has] detected large quantities of advanced weapons, including air defence systems, artillery, tanks, and armoured personnel carriers being transferred to separatist forces in eastern Ukraine," he said.

"Russia is reinforcing and resupplying separatist forces in a blatant attempt to change the momentum of the fighting, which is currently favouring the Ukrainian military."

More than 1,000 Russian troops are operating inside Ukraine, both supporting the separatists and fighting on their side, according to Nato.

But Russia's ambassador to the EU, Vladimir Chizhov, said Nato had "never produced a single piece of evidence" for its accusations. He said the only Russian soldiers on Ukrainian soil were 10 paratroopers captured earlier this week.

image copyright AFP image caption A separatist digs a trench east of Donetsk, where heavy fighting with government forces continues

In international reaction:

British Prime Minister David Cameron warned that if Russia failed to find a political solution to the crisis, "she should be in no doubt that there will be further consequences"

Polish Foreign Minister Radoslaw Sikorski called the deployment of Russian troops an "aggression" and said international action was needed

German Chancellor Angela Merkel demanded an explanation from Russian President Vladimir Putin amid the reports of an incursion

French President Francois Hollande said it would be "intolerable" if Russian troops were in Ukraine, and demanded that Russia stop sending aid to the rebels

'Sharp aggravation'

On Thursday, Ukrainian President Petro Poroshenko called an emergency meeting with his security council to discuss "the sharp aggravation of the situation in Donetsk region... as Russian troops were actually brought into Ukraine".

"The situation is extremely difficult, but it is manageable enough for us not to panic and continue calculating our actions," he told security chiefs.

Meanwhile Prime Minister Arseny Yatsenyuk said Russia had "unleashed a war in Europe", adding that the world should take "effective steps".

media caption Ukrainian prime minister Arseniy Yatsenyuk: "Russian military boots are on Ukrainian ground'

Government forces had made significant advances against the separatists in recent weeks, but these gains seem in doubt with rebels now operating in two distinct areas of Donetsk region.

Separatist leader Alexander Zakharchenko told Russian TV that 3-4,000 Russian citizens were fighting in their ranks.

He said many of the Russians were former service-people or current service personnel on leave, insisting that all were volunteers.

Ukraine's security and defence council confirmed reports that Novoazovsk had been captured by the rebels, whom they described as "Russian troops".

It said it had withdrawn its forces to save lives, and that Ukrainian soldiers were now reinforcing the defences of the strategic port city of Mariupol.

The port has until now been peaceful and cut off from rebel positions.

image copyright AP image caption Ukrainian forces are being deployed to help defend the southern city of Mariupol

Keir Giles, analyst, Conflict Studies Research Centre, Oxford

President Vladimir Putin received authorisation from parliament to use troops in Ukraine in March. But in June, during an easing of tension, he asked for that authorisation to be revoked.

The statements that the Russian soldiers in eastern Ukraine are "volunteers" and "on leave" both add a layer of implausible deniability, and get around Russia's own constitutional and legal safeguards against sending servicemen abroad without the proper authority.

Meanwhile, Russia's next steps are an open question. One concern is that the more direct involvement of Russian troops may create the conditions for a "humanitarian intervention" by Russia, using "peacekeepers".

image copyright Reuters image caption Shelling is continuing in Donetsk, hitting buildings including this school

image copyright Reuters image caption Railway lines in eastern Ukraine have been destroyed in the fighting

Pro-Russian fighters have been trying for weeks to break out of an area further north in the Donetsk region where they are almost encircled.

Analysts say the separatists could also be seeking a land link between Russia and Crimea, which would give them control over the entire Sea of Azov.

Russia annexed the Black Sea peninsula of Crimea from Ukraine in March.

War in eastern Ukraine: The human cost