Ukraine said on Sunday that a convoy of 106 vehicles had entered its eastern territory from Russia without Kiev's permission and accused Moscow of once again using humanitarian aid shipments to send weapons and ammunition to separatist rebels.

In the separatist-held city of Donetsk, fighting intensified at the local airport, a Reuters witness said. There has been continued shelling from both government forces and the rebels, even after a peace deal signed on Sept. 5.

Months of fighting in Ukraine's separatist regions have left many without sufficient food and medical supplies. Russia has regularly dispatched shipments of aid, a move which the pro-Western Kiev government has denounced as cynical.

"The lion's share of humanitarian supplies find their way to the rebels partly in the form of food, but mostly it is ammunition, equipment and other things for combat operations," Ukrainian military spokesman Andriy Lysenko said in a televised briefing.

The latest delivery of Russian supplies is the eighth since mid-August, Russian news agency RIA cited Russia's emergency ministry as saying, adding that a total of 9,500 tonnes of mainly food, building materials and medicine had been delivered by the first seven convoys.

A Reuters witness in Donetsk said repeated volleys of artillery fire could be heard from the direction of the local airport, a strategic point that both Ukrainian troops and rebels lay claim to.

Both sides have accused each other of violating the terms of the truce, raising fears it could collapse entirely.

Lysenko said three Ukrainian servicemen and an 82-year-old civilian had been killed in the past 24 hours.

He also said Ukrainian positions in Mariupol, a strategic city on the Sea of Azov, were once again coming under attack from rebel shelling.

(Reporting by Natalia Zinets in Kiev, Maria Tsvetkova in Donetsk; Additional reporting by Alexander Winning in Moscow; Writing by Alessandra Prentice; Editing by Raissa Kasolowsky)