Soldiers with sniffer dogs and life detectors kept searching in the rubble Friday for survivors after a moderate quake hit a densely-inhabited town in Southwest China a day ago.

The 5.8-magnitude tremor, which jolted Yingjiang county of Yunnan province near the border with Myanmar, has left 25 people dead and 250 others injured.

The county has a population of 300,000 people and is home to many ethnic groups.

The youngest victim was 3 years old. Among those killed were five students. Doctors said 134 people were seriously injured.

The earthquake destroyed more than 18,000 houses and damaged around 50,000 others.

Rescuers were ordered to search every damaged building for survivors.

Gao Lei, a 21-year-old firefighter, staggered through the debris of Yongsheng Hotel along with five fellow firefighters and three sniffer dogs.

"We haven't found any sign of people buried here," said Gao.

"Though, we found three people buried in an adjacent tailor's shop. They are safe now," he said.

Many soldiers used their hands to dig through the rubble as machines could not be operated there.

More than 6,100 people, including soldiers, police officers, medical staff, and civilians, have participated in the rescue operation, saving at least 40 trapped people and sending more than 200 injured people to hospital.

The county needs 5,000 more tents for the homeless, said Zhao Jin, Party chief of Dai-Jingpo autonomous prefecture of Dehong, which administers Yingjiang.

Zhao said he had asked the provincial government for help.

The provincial and local governments have earmarked 23 million yuan ($3.49 million) in emergency aid to the quake-hit regions.

"We are now short of disinfectant, crucial for the post-quake epidemic prevention work," said Zhang Tao, president of the People's Hospital of Yingjiang.

About 60 injured people have to stay in tents and 74 others were transferred to other hospitals for surgery as part of the hospital's building was damaged and power supply has not been fully resumed there, Zhang said.

The quake first hit the county at 12:58 pm, followed by seven aftershocks measuring up to 4.7 on the Richter scale.

Experts have not ruled out the possibility that stronger quakes might hit the region and they could not say that the first magnitude-5.8 tremor was the main quake.

Prior to the quake, more than 1,200 minor tremors were recorded in the region over the last two months.