Police searched for two homeless scavengers who apparently stole bronze fittings from gas pipes and triggered an explosion at an apartment building Tuesday that killed at least 41 people, authorities said.

The blast sheared off a section of the nine-story prefabricated apartment building in this White Sea port about 600 miles north of Moscow (search).

Two dozen people were rescued from the rubble, said Emergency Situations Ministry spokeswoman Irina Andriyanova.

Rescuers worked through the night to pull bodies from the remnants of the building, which was torn apart by an apparent natural-gas explosion (search) Tuesday. Forty bodies were recovered and one woman who had been pulled out alive died overnight in a hospital, said a ministry duty officer in Arkhangelsk (search).

Alexei Kalinin, deputy to the top regional emergency official, said the dead included five children.

Prosecutors opened a criminal investigation.

Authorities were searching for two men, said Igor Avtushko, a spokesman for the regional Interior Ministry.

The men allegedly were carrying metal pipes and tools, and police believed they had opened the gas valves in order to steal the bronze fittings that seal them.

Avtushko said authorities found fixtures missing in two neighboring buildings but crews were able to fix the gas leaks in time.

"These damned vagabonds unscrewed these valves a hundred times in the past, but then it didn't lead to explosions," said Andrei Seleznyov, 52, who lives in a neighboring building. He added that they had been systematically stealing the hardware.

Thieves pilfer power lines, municipal facilities and industrial equipment throughout Russia in search for copper, bronze and other metals to sell for scrap.

In addition, neglect of safety precautions has led to frequent gas explosions in Russian apartment buildings and public facilities.

Authorities earlier had feared sabotage or terrorism, even though the first emergency crews to respond reported a strong odor of gas. Tension is high in Russia after a series of terrorist attacks blamed on Chechen rebels. In 1999, explosions blamed on rebels ripped through apartment buildings in Moscow and two other cities, killing about 300 people.

Tuesday's blast hit at 3:25 a.m. local time, when most residents of the building were in bed.

"We were awakened by a terrible noise," a 40-year-old man who identified himself as Igor and lives in the adjoining section of the apartment building, told Arkhangelsk's Pravda Severa newspaper. "The wall of our bedroom came crashing down on the bed. ... We were in a state of shock."

"Through a pillar of dust I saw the street, just our street instead of the wall," he said. He described hearing "heartbreaking cries."

Vadim and Anna Kurochkin were awake in their ninth-floor apartment when the blast occurred and they were thrown out on their sofa, landing safely with no injuries.

Their 9-year old son, Artyom, was on the balcony, which miraculously didn't collapse, and he was rescued by firefighters, Irina Budnik, a spokeswoman for the local fire brigade told Pravda Severa.

Building residents had reported smelling gas to the local emergency gas service before the explosion, but that its workers didn't come until the blast occurred, NTV television said.

Rescue crews and equipment were dispatched by air from Moscow and northern Karelia to help in the search.