Ukrainian border guards stand grim-faced and nervous at the remote Marynivka checkpoint on the frontier with Russia, fearing an attack by pro-Moscow separatists at any time.
Last week they fought off an assault by up to 150 rebels seeking control over supply routes from Russia to bring in arms and other war materials, forcing them to abandon two armored personnel carriers strafed with machine-gun fire.
A weary border guard, wearing a camouflage T-shirt and a cap with a Ukrainian national emblem, said he fears for the worst if the authorities in Kiev do not send help.