BAGHDAD - A helicopter contracted by the U.S. Defence Department through a Canadian charter company was shot down by missile fire Thursday north of the Iraq capital of Baghdad, the Bulgarian Defence Ministry said. Nine people were killed, including three Bulgarians, officials said.

"The helicopter was shot by missile fire around 2 p.m. local time" north of Baghdad, the Defence Ministry said in a statement. It did not provide the nationalities of six others killed.

In Washington, a senior Defence Department official said there were six civilian contract workers aboard the aircraft. The official, who spoke on condition of anonymity, said he did not know the nationalities of those six victims or their employers.

Paul Greenaway, senior air charter manager with Toronto-based SkyLink Aviation, confirmed from Iraq that his company had handled the charter, but without a flight manifest he couldn't say whether any Canadians were aboard.

Greenaway said the flight was "a routine charter from Baghdad to Tikrit." Tikrit, 130 kilometres north of Baghdad, is the hometown of deposed Iraqi leader Saddam Hussein.

The aircraft was hit by at least one surface-to-air missile, according to initial information, said Sotislav Bozhkov, a sales manager at Heli Air, the Bulgarian company that owns the Russian-built Mi-8 helicopter.

Video footage showed burning wreckage scattered across a wide area.

The helicopter had been chartered to SkyLink to transport personnel involved in Iraqi reconstruction, said Heli Air manager Mihail Mihailov

He identified the three Bulgarian crew members as pilots Lyubomir Kostov and Georgi Naidenov, and mechanic Stoyan Anchev. He did not identify the six passengers.

Bulgaria has a 460-member infantry battalion in the Iraqi city of Diwaniyah serving under Polish command, but Defence Ministry spokesman Vladimir Prelezov said no members of the Bulgarian military contingent were on board.

The battalion's mission ends in July, but the Bulgarian government has said its mission will be extended through the end of the year.