SHANGHAI, Aug. 14 (Xinhua) -- Firefighters are struggling to control a blaze near the top of the construction site for China's tallest building in Shanghai.

Thick smoke was reported coming from the International Financial Center in the city's Pudong New District at around 4:30 p.m. on Tuesday.

The building has a planned height of 492 meters, and already exceeds 400 meters.

No casualties have been reported.

Construction of the 101-storey building began in November 2005. It has a designed height of 492 meters and it is expected to be China's tallest building on completion.

The cause of the fire is unknown.