An additional 440 Chinese Muslims left for the annual pilgrimage to the Muslim holy city of Mecca in Saudi Arabia on Friday night and Saturday morning.

This number includes 136 from Ningxia Hui Autonomous Region and 304 from Qinghai Province in northeast China.

The chartered planes took off from Zhongchuan Airport in Lanzhou, capital of northwestern Gansu Province, at about 9:50 p.m. Friday and 3:15 a.m. Saturday, according to airport officials.

The remaining of 2,400 pilgrims in Ningxia will leave for the pilgrimage before Oct. 31. The rest of 1950 pilgrims in Qinghai will leave before Oct. 26.

About 13,000 Chinese Muslims will go on the pilgrimage to Mecca this year, according to Yang Shuli, assistant president of the China Islamic Institute.

China has some 23 million Muslims in more than 20 provinces, autonomous regions, and municipalities, according to official statistics.

In 1997, the first chartered plane for Chinese pilgrims flew from Beijing to Jeddah, an important gateway to Mecca. Direct chartered flights later linked Beijing, Lanzhou, Urumqi, Yinchuan, and Kunming to Medina, the second holiest city north of Mecca.

Mecca, the birthplace of the Prophet Mohammed, is a shrine for Muslims across the globe. A pilgrimage to Mecca is considered a religious duty that must be carried out at least once in the life of every able-bodied Muslim who can afford to do so.