Relief troops are approaching Wenchuan County on foot, the epicenter of a quake that jolted southwest China's Sichuan Province Monday afternoon.

The authority has not given a specific number of the rescuing troops approaching the epicenter, but about 100 officers of the armed police forces advancing to Wenchuan on foot has been accessed via satellite phone.

Li Zaiyuan, head of the unit, told that there was only 70 kilometers toward their destination.

Setting out from Maerkang at 20:00 on Monday, about 200 kilometers away from Wenchuan, the unit has walked for nearly seven hours on foot and met a number of aftershocks and sliding rocks in heavy rains.

"I have seen many collapsed civilian houses and the rocks dropped from mountains on the roadside are everywhere," said the unit head, "We are on the way on foot."

The epicenter of the quake, measuring 7.8 on the Richter scale, is located 31 degrees north latitude and 103.4 degrees east longitude.

The road from Dujiangyan, a city northwest of the provincial capital Chengdu, to Wenchuan was blocked by rock and mud slides, holding up rescue, medical and other disaster relief teams, a witness said via mobile phone.

Premier Wen Jiabao asked military personnel waiting in the city to enter the area as soon as possible even if they had to walk to Wenchuan.

The earlier the troops arrived, the more lives they could save, he said.

Wen pledged that the military will provide as many soldiers and officers as the quake relief work needs to save trapped people.

So far the People's Liberation Army and the Armed Police Forces have mobilized more than 20,000 personnel.

Another 20,000 airborne troops will be dropped to the areas and 10,000 will take railways to join the quake relievers. More than 3,000 police officers will also be dispatched.

In addition, two heavy aerotransports fully loaded with medical equipment and disaster relieving experts have arrived at an airport on the outskirt of Chengdu. They will take military trucks heading for Wenchuan.

Editor: Yan