A topping-out ceremony was held Saturday for China's tallest building, which remains under construction until its scheduled completion in 2015.

Construction workers placed the last beam on the main structure of the Shanghai Tower in the Lujiazui financial and trade zone in Shanghai's Pudong District Saturday morning.

The 125-story building, now 580 meters high, is scheduled to reach a final height of 632 meters upon completion in 2015.

The tower will become a landmark building in Shanghai after it opens, said Fang Qingqiang, chief engineer of the construction project.

The building includes offices, commercial space, a five-star hotel, exhibition and conference halls and recreational facilities, said Fang.

The topping-out ceremony marks the start of attracting businesses to the complex, said Gu Jianping, president of Shanghai Tower Construction and Development Co., Ltd.

The tower will help meet demand for high-end offices as the city seeks to build it into an international financial center and free trade zone, Gu said.