At least five people were killed on Monday when oxygen canisters exploded in the intensive care unit of a Ukrainian hospital and caused several floors to collapse, officials said.
Prime Minister Yulia Tymoshenko, in the midst of a bitter election campaign, set off for the scene of the blast in the eastern Ukrainian city of Lugansk close to the border with Russia, her office said.
"As a result of a violation of security rules in the intensive care unit of hospital number seven of Lugansk, oxygen canisters exploded," it said in a statement.
"Several floors of the hospital collapsed," it said.
Ukraine's emergency situations ministry said that as a result of rescue efforts "three people have been saved and the corpses of five people have been extracted".
The health ministry said in a statement that 261 patients and 350 medical personnel were in the hospital at the time of the blast. It said seven people had so far been rescued from the rubble.
Local Internet newspaper Vostochny Variant said the third and fourth floors of the building had collapsed onto the second.