A series of powerful explosions at an arms storage complex on the outskirts of Sofia rocked the Bulgarian capital at around 6:30 am local time, authorities and eyewitnesses said.

The blasts happened near the village of Chelopechene, on the eastern outskirts of Sofia. There are no casualties. The defense ministry said guards at the four dumps in the complex were evacuated.

Rescuers had been unable to reach the main blast site as ammunition continued to detonate, police and civil defense officials said.

"This morning at 6.30 am (0330 GMT) a fire has broken out in the area of Chelopechene and explosions followed," the ministry of emergencies said in a statement.

The site of the military unit has been cordoned off by the police.

The blasts shook apartment blocks and broke windows in eastern districts of Sofia, eyewitnesses said.

"The house was shaking, I thought it was an earthquake," a tearful woman, who lives in Chelopechene, told national radio.

Officials urged people to stay at home and close their windows.

"Our checks show that there are no harmful emissions in the air and mass evacuation is not needed," said Valeri Mladenov, head of civil defense in Sofia.

Sofia Airport was closed at 6:50 this morning, the airport director Plamen Stanchev said on bTV. All flights are canceled until 14:30 today.

The explosions will continue for at least 24 hours more. The storage complex holds some 20 tonnes of T.N.T, which means we can expect more blasts that would be felt in an area of 7-8 km, Pavlin Dimitrov, general secretary of the Ministry of Interior said for Darik Radio.

People within an 8 km perimeter around the Chelopechene storage complex will be evacuated.

Sources: BGNES, Darik Radio, bTV, Reuters, the Ministry of Defense