A Xinhua reporter saw plumes of heavy smoke arose from Ain-Zarah area in east Tripoli.
It is believed that the target is an ammunition storage site of the Libyan government.
The reporter said two other explosions were heard in the area about a half hour after the first explosion. NATO planes were seen hovering above Tripoli.
Rebel commanders said their fighters captured the town of Bir Ghanam, 80 kilometres (50 miles) south of the Libyan capital, on Saturday.(*)
Editor: Jafar M Sidik
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