KYIV, Ukraine (AP) — Rescuers are searching for survivors in the ruins of a theater ripped apart by Russian airstrikes in the besieged city of Mariupol, while ferocious Russian bombardment killed dozens in a northern city over the past day, according to the local governor. Hundreds of civilians had taken refuge in the theater basement and were trapped when strikes collapsed the building onto their shelter. It is still not known if there were deaths or injuries. A local governor says at least 53 people were killed over the past day by ferocious Russian bombardment on the northern city of Chernihiv, including people lined up to buy bread. Residents were hiding in basements. “The city has never known such nightmarish, colossal losses and destruction,” the governor said.