A methane gas explosion injured three members of a search team Monday and delayed efforts to reach about 90 miners believed killed Friday by a fire and explosion in a coal mine.

"A strong air blast stopped the rescuers, who came out of the pit safely," said Miroljub Stefanovic, Serbian chief mining inspector and the head of the search operations at the Morava pit in Aleksinac, 125 miles southeast of Belgrade.Three members of the 14-member search team were rushed to a hospital, but a doctor said they suffered minor injuries and were expected to be treated only a few days.

Friday, fire swept through the Morava pit 2,150 feet underground in the Aleksinac mine, 124 miles southeast of Belgrade. About 70 miners escaped and about 90 others remained trapped in the pit, where mine officials said they died of suffocation and fire.

Officials in the Serbian town of Nis, close to Aleksinac, have detained four mine workers who allegedly started the fire accidentally as they were using welding equipment in the pit. The four escaped after trying to put out the blaze.

Rescue teams immediately began trying to reach the trapped 90 miners.