President Hu Jintao on Monday ordered all-out efforts to help those affected by a major earthquake measuring 7.8 on the Richter scale that jolted Wenchuan County of southwest China's Sichuan Province at 2:28 pm today.

Premier Wen Jiabao was on his way to the area to direct the rescue work.

The Chengdu Military Area Command has dispatched troops to help with disaster relief work in the earthquake-stricken area, military sources said.

Tian Yixiang, officer with the emergency office of the People's Liberation Army (PLA), said the troops will assist local government in Wenchuan county to gauge the current situation and to help with disaster relief work.

A major earthquake measuring 7.8 on the Richter scale jolted Wenchuan at 2:28 pm today, the State Seismological Bureau said. The epicenter of the quake was located 31.0 degrees north latitude and 103.4 degrees east longitude, the bureau said.