An Albanian army base stocking obsolete munitions for destruction blew up in a chain of massive blasts on Saturday killing at least four people and officials said many more workers at the site may have been killed.

Four people were confirmed dead and some 200 injured, and rescue teams were scouring the devastated scene. Hospitals took in scores of injured suffering burns, concussion, broken limbs, or cuts from flying glass and shrapnel.

"Larges areas have not yet been checked because the explosions continue," said a statement from the office of Prime Minister Sali Berisha, whose government has pledged to destroy dangerously unstable explosives left over from communism.

The explosions began as Albanian and U.S. teams were moving stocks of World War Two-era bombs, bullets and shells stored at the base, a central collection point for the arsenal amassed by Albania's Stalinist-era dictatorship.

Albania hopes to be invited to join NATO next month.

Many were hurt as enormous shockwaves hit nearby villages and cars passing by on the adjacent highway. A company involved in destroying the munitions said there were 3,000 tonnes of explosive material stocked at the site.

WORKING IN GROUPS

Visiting one hospital, Berisha asked a wounded man how many people were inside the base when the explosion occurred.

"We were working in 21 groups made up of three people. I and 14 others managed to get out," he told Berisha.

His office later quoted witnesses as saying the first explosion was not that big, allowing many of the estimated 110 workers on the site to get out.

"Ten minutes passed before the biggest blast and many workers used this time to flee," a press statement said. "The government is trying to identify all the workers one by one, but the situation is difficult and the explosions continue."

A Reuters cameraman saw "terrified people were leaving the area on foot along the highway" and cars with broken windows abandoned in the middle of the road.

Albanian TV showed houses torn apart, walls and roofs caved in. One report said unexploded shells, including 50-year-old artillery rounds, were lying scattered around the area.

Amateur video shot five hours later recorded flames still burning amid the crackle of small explosions in a sea of rubble.

Residents of the village of Gerdec had taken shelter in concrete bunkers built by late dictator Enver Hoxha, and some fled from the valley up onto the hillsides above the base.

Spokeswoman Arlinda Causholli said windows and glass doors were shattered at Tirana's brand new airport, a few kilometres from the base. Flights were suspended for half an hour.

The U.S. embassy could not confirm one report that U.S. citizens had been at the site. U.S. civilian contractors have been involved in the de-commissioning project over the years.