EU foreign policy chief Josep Borrell said yesterday that Russia has massed over 150,000 troops along the Ukrainian border and in the annexed Crimea peninsula.

"It is the highest Russian military deployment at Ukrainian borders ever," Borrell told journalists after talks involving Ukraine's foreign minister, refusing to disclose the source of the figure.

"The risk of further escalation, it's evident," he warned.

Tensions have spiralled over the build-up of Russian troops around its southwestern neighbour as an intensification of clashes with Moscow-backed separatists has fuelled fears of a return to widespread fighting in Ukraine.

Moscow's military says it is conducting exercises along its frontier in response to moves by Western military alliance Nato that "threaten Russia".

Defence Minister Sergei Shoigu said last week that "two armies and three airborne units were successfully deployed" to the Russia's western border and that the drills would be over "within two weeks".

Ukraine is pushing the West for more practical support as it looks wwwwwto deter any further aggression from Moscow.

Meanwhile, Ukraine's foreign ministry yesterday said it had expelled a Russian diplomat in a tit-for-tat move after Moscow ordered a Ukrainian consul in Saint Petersburg to leave Russia, accusing him of trying to obtain sensitive information.

Kiev's Foreign Minister Dmytro Kuleba pressed the EU to prepare "a new set of sectoral sanctions" against Russia in talks with his counterparts from the 27-nation bloc yesterday.

But Borrell said that there were currently no further sanctions being proposed or under consideration.