One hundred and sixty people, many of them Americans, are feared dead or injured after a series of large explosions at an army base on the outskirts of Tirana, the capital of Albania, officials have said.

People suffering with burns, concussions and broken limbs were rushed to local hospitals following the blasts, believed to have begun while teams were dismantling munitions at a store base. Many of the injuries were a result of flying glass or shrapnel.

"We do not know the exact number, but we fear the worst for the three teams, each of 21 people, working there at the time," said Juela Mecani, spokeswoman for the country's prime minister, Sali Berisha. "Several were US citizens."

A spokesman for the Albanian interior ministry, Avni Neza, said army and police forces were trying to reach the area in armoured cars. "Helicopters have not yet managed to land because the explosions continue," he said.

A Reuters cameraman who quickly arrived at the scene described people trying to escape: "Terrified people are leaving the area on foot along the highway, women and children. Cars with broken windows have been abandoned on the highway."

The force of the explosion was so strong that it was felt at the seaside resort of Durres, 20km away. People living in the nearby village of Gerdec took shelter in concrete bunkers while others fled to the hills.

At Tirana airport, several kilometres from the base, glass doors and windows shattered. "We evacuated passengers from the affected area and suspended flights for around 30 minutes," said Arlinda Causholli, a spokeswoman for the airport.

Local media reports suggested that five people were in a coma while Tirana residents were rushing to hospitals to donate blood. One witness said there had been 100 people at the base. The US embassy in Tirana could not confirm whether US military personnel were present at the site or not.

Albania is required to dismantle its obsolete Stalinist-era arsenal and modernise its armed forces in order to qualify it for an invitation to join Nato next month.