Air Malta's flight KM 785 from Sofia, Bulgaria to Malta was delayed by several hours yesterday due to an explosion at an old ammunition dump a few kilometres away from the airport.

Air Malta said that passengers on the flight, which was due to arrive in Malta at 8 a.m., were already on board the aircraft on the ground at Sofia airport when the blasts occurred.

The airline said that at no time were passengers or the aircraft in any danger but as a precautionary measure the passengers were asked to disembark and were given refreshments and meals.

Sofia Airport was closed for a long time after the explosion. The flight was due to arrive after 11 last night.

Air Malta said it did everything possible to minimise any discomfort. It apologised to its customers for the delay caused by circumstances beyond its control.

Meanwhile reports from Bulgaria stated that a series of powerful explosions rocked an arms disposal depot storing 1,500 tonnes of obsolete munitions outside Sofia yesterday, injuring three people, shaking apartment blocks and panicking thousands.

Sofia's international airport to the east of the capital was shut temporarily after debris from the blasts fell on the runway and incoming flights were diverted to the southern city of Plovdiv.

The explosions followed a fire at the complex near the village of Chelopechene on the eastern edge of the Bulgarian capital, police and civil defence officials said.

The explosions continued for about eight hours. Authorities said smaller blasts were likely in the next 24 hours and urged Sofia's nearly two million citizens to stay calm.