(CNN)

At least 28 have been killed in an attack on a building in the town of Lysychansk in the Russian-occupied region of Luhansk in eastern Ukraine, the region’s Moscow-installed head said Sunday.

In a statement on Telegram, the head of self-proclaimed Luhansk People’s Republic Leonid Pasechnik said emergency services had rescued 10 people from under the rubble after what he said was a Ukrainian attack on a building housing a bakery on Saturday.

Pasechnik said Sunday has been declared a day of mourning in the Luhansk People’s Republic for the victims of the attack.

Ukraine’s defense ministry has not commented on the incident.

Lysychansk was taken over by Russian forces in July 2022, becoming the last town in the key region of Luhansk in eastern Ukraine to fall.

Ukraine has been escalating its attacks on Russia and Russian-controlled territory as its ground offensive stalls.