Albanian PM Sali Berisha says a "considerable" number of people have been killed in huge explosions at an arms depot near the capital, Tirana.

His spokeswoman Juela Mecani said four bodies had been recovered, but more than 60 people - including US citizens - were at the scene at the time.

More than 150 people, many of them civilians from the surrounding area, including children, were injured.

Military experts were disposing of old shells at the time of the blasts.

They were reported to be being assisted by employees of a US company contracted by Nato to help the Albanian army dispose of surplus munitions.

The explosions at the army depot in Gerdec village, some 10km north of Tirana, were heard more than 50km (30 miles) away.

The initial explosion was followed by a series of blasts, and ammunition continued to detonate for hours.

Attempts to fly rescuers into the area by helicopter were thwarted by the continuing explosions, and armored vehicles were used to ferry rescue units into the area.

Injured people were taken to nearby hospitals. Local media reports said their injuries included burns, concussion, broken limbs, and cuts from flying glass and shrapnel.

"The number of dead is considerable," Berisha told reporters.

Berisha - who visited some of the injured in hospital - said he could not rule out human error as the cause of the explosions, but added that the ammunition could have exploded spontaneously because of its age.

"The problem of ammunition in Albania is one of the gravest, and a continuous threat," Berisha said.

"There is a colossal, crazy amount of it dating back to 1945."

Flights were suspended at Mother Teresa Tirana International Airport, several kilometers from the base, for 30 minutes after windows there were shattered.

The US embassy in Tirana said it was unable to confirm that there were US citizens at the depot.

PHOTO CAPTION

An Albanian military policeman watches smoke billowing from an explosion at an army base some 16 km (10 miles) from Tirana March 15, 2008.

BBC