HONG KONG, March 5 (AFP) - Chinese military forces have been put on top alert in northwestern Xinjiang province and Tibet in a bid to curb separatist activities in the troubled regions, a report said Wednesday.

The Central Military Commission has also upgraded the state of alert in Beijing and the military region of Lanzhou near Xinjiang, which has been rocked by a spate of bombings and anti-Chinese riots, the Sing Tao daily said.

In a document issued recently to regional forces, the Commission urged officers to be on alert "to prevent overseas elements from inciting unrest in Xinjiang in a move to split the motherland."

The independent Chinese-language daily also said that reinforcements of armed riot police have been sent to Xinjiang and Tibet to back up local military forces and police.

Since the beginning of the year, Xinjiang, which is dominated by ethnic Moslem Uighurs, has been gripped by a wave of separatist activity.

Three bus bombs exploded last week in the regional capital of Urumqi, killing seven and wounding 67.

According to an exiled Xinjiang separatist group in neighbouring Kazakhstan, another bomb exploded Saturday in Urumqi in a building where police officials were meeting.

The bomb attacks followed a wave of anti-Chinese unrest three weeks earlier that officially left 10 people dead in the town of Yining, near the border with Kazakhstan. Other estimates have put the death toll closer to 70.

In late December, a large bomb explosion in the Tibetan capital sparked official warnings from China of an all-out terrorist campaign by separatist groups led by the Dalai Lama.

Chinese troops took over Tibet in 1951 and the Dalai Lama fled to India in 1959 after an abortive uprising.