DONETSK, Ukraine: Ukraine said Thursday it had captured two armored vehicles belonging to the Russian military in the war-torn east as checks began on a disputed aid convoy from Moscow parked up at the border.

Fighting between government forces and pro-Russian rebels raged in Ukraine’s east as Kiev pressed on with an offensive to rout struggling insurgents ahead of a fresh round of diplomacy that will see the presidents of the two countries meet next week for the first time in months.

Some 300 Russian trucks — that Kiev fears could be used to help the insurgency — inched closer to crossing the border into rebel-held territory after Ukraine’s customs officials said they had started processing the first of the lorries after a week of wrangling.

Kiev has accused Moscow of stepping up arms supplies to east Ukraine’s rebellion while the West fears that the Kremlin could be planning to invade as a last roll of the dice. Military spokesman Andriy Lysenko said two armored vehicles from an elite Russian airborne division were seized along with documents of soldiers who had fled following a battle near the second-largest rebel stronghold of Lugansk.

The Russian military ridiculed the allegations.

Moscow denies it is arming the insurgency but Kiev’s claims will stoke tensions as Ukrainian President Petro Poroshenko prepares for a meeting in Minsk next week with Russia’s Vladimir Putin and EU officials.

On the ground, fighting continued in a string of key rebel towns as government forces refocused attempts to cut alleged supply routes from Russia to separatist-controlled areas.

Shelling in Donetsk left two people dead on Thursday, the latest fatalities in four months of conflict that has killed more than 2,200 people.