SUVA, Dec 9 (Reuters) - Fiji's military chief was still in control of the country but his whereabouts were being concealed for security reasons, an army spokeswoman said after reports of gunfire from the main barracks of the capital, Suva, on Saturday.

Commander Frank Bainimarama staged a bloodless coup on Tuedsay, toppling the government of Prime Minister Laisenia Qarase, claiming it was corrupt and soft on those behind the last coup in 2000. Fiji has had four coups since 1987.

Bainimarama was almost killed in a bloody, but failed mutiny following the 2000 coup. The military chief was forced to escape from the Suva barracks over a fence.

A Reuters witness and local residents heard sustained gunfire on Saturday in the Queen Elizabeth barracks on a hilltop overlooking Suva and said it continued for about 30 minutes.

Military spokesman Major Neumi Leweni later confirmed firing inside the barracks but said it was an unscheduled shooting exercise and that people should not be alarmed.

The barracks has no rifle range and firing practice is normally done at a range on the other side of the city.

Bainimarama has declared himself acting president and has appointed an interim prime minister, a 77-year-old former army doctor and Methodist lay preacher.

But opposition to the coup is growing steadily, with the south Pacific island nation's traditional chiefs and churches calling it illegal.

Qarase remains defiant and predicts that Fijians will soon take to the streets in protest at the coup. The military has vowed to use force to put down any opposition.

Fiji's military took out newspaper advertisements on Saturday seeking people of "outstanding character" to fill Cabinet posts in an interim government.

Fiji's capital Suva remained tense but calm on Saturday after the former British colony had its Commonwealth membership suspended overnight.