BRUSSELS, June 25 - Russian President Vladimir Putin is not done in eastern Ukraine, NATO's top commander said on Thursday, cautioning that Russia has been building up supplies on its border with Ukraine and keeping its military options open, Reuters reported.

U.S. General Philip Breedlove, NATO's supreme allied commander, said the border between Ukraine and Russia was "wide open," allowing free movement of equipment and supplies.

Force levels on Russia's side of the border had not changed much in recent months, Breedlove said, but U.S. military officials had observed in Russia a "stocking of important supplies, ammunition, etc, to levels that would support operations.”

Inside Ukraine, where pro-Russian separatists are battling Ukrainian forces, Breedlove said "we see a force that has been trained, that is led by Russian leadership, ... and is ready to do whatever mission is required of it in the Donbass (region)."

"I don’t think Mr. Putin is done in eastern Ukraine," Breedlove told reporters, and Kiev, despite Moscow's hopes, was still looking to the West for support.

A fragile ceasefire has been in force in eastern Ukraine since February, but each side accuses the other of violations. Kiev fears Russia could commit troops to a push to extend control by separatist forces deeper into Ukrainian territory.

Russia denies having troops inside the country.
NATO Secretary-General Jens Stoltenberg said it would be unwise to declare the ceasefire dead, despite violations, because it remained the "the best possible foundation for a peaceful solution.

"Without the Minsk agreements I am really afraid that the situation can deteriorate even more," he told a news conference.

Russia's annexation of Crimea last year rattled NATO allies, particularly in ex-Soviet Baltic states. With their Russian minorities, they fear Moscow could stir unrest there. Moscow denies any such intention.

Ukrainian Defense Minister Stepan Poltorak told a news conference some alliance members might consider sending arms if the ceasefire broke down completely. Lithuania has said it has provided weapons to Ukraine.

Stoltenberg said NATO had also launched a scheme to share air traffic information with Ukraine from regional traffic control centers in Poland, Norway and Turkey. NATO officials said the scheme was aimed at countering terrorism or hijackings. (rt/ez)