US can't confirm Ukraine/Russia attack reports

Ukraine said its artillery destroyed part of a Russian armoured column that entered its territory.

FILE: A Ukrainian soldier stands guard at a check-point near the eastern Ukrainian city of Donetsk on 11 August 2014. Picture: AFP.

KIEV - The United States (US) says it cannot confirm reports that Ukraine has disabled vehicles in a Russian convoy inside of Ukraine.

This comes after Ukraine said its artillery had destroyed part of a Russian armoured column that entered its territory overnight.

The US says Russia has no right to send vehicles or cargo of any kind into Ukraine without permission from that country's government.

Russia has denied its forces crossed into Ukraine and has accused Kiev of trying to sabotage aid deliveries to conflict areas.

Meanwhile, Moscow accused Kiev of trying to sabotage aid deliveries to eastern areas torn by fighting between pro-Russian separatists and the Western-backed government of Moscow's former satellite.

In a call to US Defense Secretary Chuck Hagel, as reported by Russia's state news agency RIA, Defence Minister Sergei Shoigu said Moscow was "seriously concerned" by increased NATO activity and called for a ceasefire to get aid into Ukraine. The agency did not specify what Western military movements he meant.

The Pentagon said in a statement that Hagel had sought clarification about the Russian convoy during the phone call and was "guaranteed" it did not include Russian military personnel and would not be used as a pretext for intervening in Ukraine.

NATO said there had been a Russian incursion into Ukraine, which is not a member of its mutual defence pact, but it is avoiding calling it an invasion. Other European capitals accused the Kremlin of escalating a conflict that has revived Cold War-era animosities and chilled the region's struggling economies.

German Chancellor Angela Merkel urged Russian President Vladimir Putin in a phone call on Friday to help defuse the crisis and halt the stream of weapons and armed personnel into Ukraine, her office said.

"In view of the need for an urgent ceasefire she urged the president to help de-escalate the situation and in particular to halt the stream of weapons, military advisers and armed personnel into Ukraine," spokesman Steffen Seibert said.

Kiev and its Western allies have repeatedly accused Russia of arming pro-Moscow separatist rebels in eastern Ukraine, and of sending undercover military units onto Ukrainian soil. They have also expressed concern Russia may use an aid convoy it has assembled on the border as a pretext for stoking the conflict.

It was not clear whether the armoured column was officially part of the Russian army on active service. But evidence of Russian military vehicles captured or destroyed on Ukrainian territory would give extra force to Kiev's allegations - and possibly spark a new round of sanctions against the Kremlin.

Andriy Lysenko, a spokesman for the Ukrainian military, told a news briefing that Kiev's forces had picked up a Russian military column crossing the border under cover of darkness.