Ukraine fighting rages despite truce

Pro-Russian separatists have carried out several attacks on Ukrainian troops despite a unilateral ceasefire declared by Kiev, Ukrainian officials say.

They say at least six border guards were injured in shelling by the insurgents in the east overnight.

The rebels earlier dismissed the truce called by President Petro Poroshenko, the first step of his peace plan.

Meanwhile, the US imposed sanctions - including asset freezes - against seven pro-Russian leaders in Ukraine.

Western leaders have threatened additional sanctions against Russia, which they accuse of stoking tension in Ukraine. Moscow denies the claim.

In a separate development, President Vladimir Putin ordered forces in Russia's central military district to be put on full combat alert for a week.

The drill does not affect troops near the border with Ukraine. Putin has ordered several such alerts to test combat readiness in recent months.

BUFFER ZONE

Overnight, the separatists attacked three Ukrainian border posts in the Donetsk and Luhansk regions, Kiev said.

The rebels shelled the posts with rocket and mortar fire, injuring six border guards.

The gunmen also attacked Ukrainian forces outside the Kramatorsk airfield, in the Donetsk region.

The Ukrainian forces returned fire, and all the attacks were repelled, Kiev said. However, Ukraine's border guard service said its personnel at the Izvaryne post, Luhansk region, were forced to retreat into Russian territory.

A number of casualties were reported among the separatists.

Poroshenko on Friday declared the week-long ceasefire to give rebels time to disarm. It became effective from 22:00 local time (19:00 GMT).

The president also unveiled proposals for the peace plan involving decentralising power, holding early elections, and creating a 10km (six-mile) buffer zone on the Ukrainian-Russian border.

A senior rebel commander told Ukrainian news agencies the insurgents would not disarm until government troops had left the east.

The Kremlin dismissed the truce, saying it was "not an invitation to peace and negotiations but an ultimatum".

'SCALPEL SANCTIONS'

The US and European Union leaders have previously imposed sanctions after Russia annexed the Ukrainian region of Crimea in March.

On Friday, the US Treasury Department said it had blacklisted seven rebel leaders, including self-proclaimed mayors, governors and commanders in chief of cities under siege by Ukrainian forces.

Their assets in the US will be frozen and US firms will be banned from dealing with them.

US officials also said "scalpel" sanctions against Russia's defence, finance and high-tech industries were being considered.

US President Barack Obama had spoken separately to French President Francois Hollande and German Chancellor Angela Merkel, a White House statement said.

The leaders had agreed the US and EU would "co-ordinate additional steps to impose costs on Russia" if Moscow did not try to "de-escalate the situation in eastern Ukraine", the statement added.

Washington says Russia is providing the separatists with military equipment, including tanks, and is building up troops on its border with Ukraine.

Moscow denies the claim.