BEIJING, June 13 (Xinhua) -- Chinese Premier Wen Jiabao has urged government officials to strengthen efforts to control and prevent sandstorms and the environmental degradation.

China faces a serious threat of desertification, requiring afforestation efforts to be stepped up, Wen told a meeting attended by sandstorm control experts on Monday.

"It's long-term, arduous work fighting the sand, and China should improve sand control mechanisms," Wen said.

Organizations under the State Council should strengthen cooperation to improve sand control policies, and increase investment in desert control, said Wen.

He also encouraged residents of desert areas to participate in efforts to stop desertification.

At the meeting, Chinese scientists and experts offered suggestions on the types of trees to be planted in deserts, environmental rehabilitation in the source regions of sandstorms, adjustment of the agricultural structure in northwest China, and sandstorm monitoring and alarm systems.

They also called for greater international cooperation in the prevention of sandstorms.

Sandstorms have hit China 17 times this year, with 12 of them crossing international borders. China, Japan, the Republic of Korea and Mongolia have agreed on a plan to jointly fight sandstorms.

The frequent sandstorms have rung an alarm bell for China.

In a serious storm this spring, sand covered about one-eighth of China from April 14 to 18 and about 330,000 tons of sand fell in Beijing over one night.

A strong sandstorm hit northwest China in April, killing one person in Xinjiang Uygur Autonomous Region and forcing dozens of trains to halt for safety reasons.

Deserts in the western regions of China were still expanding, said Wu Zhongze, an official with the State Forestry Administration. Much of the farmland in Qinghai and Gansu provinces and Xinjiang Uygur Autonomous Region was turning sandy.

Apart from climate factors, experts blame the advance of deserts on rampant logging, over-grazing of grassland, excessive farming and reckless use of water resources.

China suffers from one of the world's most serious desertification problems, with 2.64 million sq km -- or 27.46 percent of its territory -- turned to desert. Enditem