BRUSSELS: EU ministers expressed concern Friday at reports of a Russian incursion into eastern Ukraine and threatened a vigorous response if Moscow failed to reverse course.
"I am very alarmed by the report," said British Foreign Secretary Philip Hammond as he arrived for talks primarily to discuss the crisis in Iraq.
"If there are any Russian military personnel or vehicles in Ukraine they need to be withdrawn immediately or the consequences will be very serious," he said.
Ukrainian authorities confirmed British media reports Friday that a small number of Russian armoured vehicles had crossed into Ukraine, not far from where an aid convoy from Moscow was trying to reach pro-Kremlin separatists.
"We are deeply concerned by Russian behavior over the last months but also the last hours," said Danish Foreign Minister Martin Lidegaard.
"We think that the Russian authorities should be aware that both in the EU and the U.S. we have a very strong commitment to respond to any new aggression from Russia," he added.
The incursion was a "gross violation of international law," said Swedish Foreign Minister Carl Bildt, adding that the situation in eastern Ukraine was "disastrous."
"Gangsterism" by pro- Moscow separatists was rampant, Bildt said.
"The so-called People's Republic of Donetsk and Lugansk no longer have people," he said in reference to the separatists.
Germany remained cautious on the reports, with Foreign Minister Frank-Walter Steinmeier speaking only of "repeated difficulties" in the last hours.
Steinmeier said he welcomed news that Russia would allow the inspection of the truck convoy that many are worried is a pretext to supply fighting power to separatists.
"We are at the moment mainly concerned with the humanitarian convoy but actually the next step is about more: it's about what can be done to make the weapons fall silent," Steinmeier said.
Some four months of fighting have left over 2,000 people dead and forced some 285,000 to flee their homes.