Russian sabotage groups tried to break through into Ukraine, according to Kharkiv's governor, as Moscow steps up its shelling of the region.
Oleh Synehubov said the attempts were rebuffed by Ukraine's armed forces, who "confidently hold their positions" and have not lost "a single metre".
He said shelling continued in the town of Vovchansk throughout the night, but the Russian group "does not pose a threat to Kharkiv".
"Its forces are sufficient only for provocations in the northern direction," he claims.
But he did call on residents to stay in shelters as Russia "makes no difference" between military and civilian targets.