* Government says attackers were defeated
* Tanks briefly deployed in central Kinshasa
* Base was also targeted by gunmen in December
KINSHASA, July 22 (Reuters) - Gunmen attacked a major military base in Democratic Republic of Congo's capital, Kinshasa, on Tuesday but the government said the situation had been quickly brought under control.
Witnesses said shooting died down after about half an hour. Security forces deployed tanks to a busy junction in the city centre but they were withdrawn shortly afterwards.
The base, known as Camp Tshatshi, was the scene of fighting in December last year when gunmen also attacked state television and an airport in the capital.
"Armed men attacked Camp Tshatshi some time between 1400 and 1430 (1300-1330 GMT) but they were defeated," government spokesman Lambert Mende told Reuters.
Kinshasa Governor Andre Kimbuta later said on state television that the 20 to 30 attackers were civilians but did not identify them. He urged residents to return to work.
A soldier in the camp who asked not to be named said at least four attackers had been killed.
Kinshasa's main N'djili airport was evacuated on Tuesday as a precautionary measure and placed under the protection of the presidential guard, according to a staff member.
President Joseph Kabila scored a major victory last year when his U.N.-backed forces defeated eastern rebels. However, he does not have a strong grip on the vast nation and there are increased tensions over whether Kabila will try to modify the constitution to stay in power for a third term in 2016. (Reporting by Peter Jones; Additional reporting by Media Coulibaly; Writing by David Lewis and Emma Farge; Editing by Tom Heneghan)