A gas explosion in an apartment building in eastern Slovakia killed at least five people Friday. Firefighters said other people are trapped on the roof as the building burns and is in danger of collapse.

The explosion took place in the 12-story building in the city of Presov shortly after noon. Firefighters said the explosion was between the 9th and 12 floors, and several people fled to the roof.

Police called the situation "very serious."

Alena Krcova, a spokeswoman for the rescue services, said dozens of people may have been injured.

Mayor Andrea Turcanova said residents have been evacuated to nearby schools.

Slovak Prime Minister Peter Pellegrini is heading for the site with some members of his Cabinet.