A 5.0-magnitude earthquake struck southwest China on Monday, shaking a wide area that was heavily damaged in this year's Sichuan disaster, officials and residents said.

The quake hit a remote, mountainous part of the province at 2:18pm (0618 GMT) about 100 kilometres (60 miles) north of Mianyang, a city in one of the zones worst affected by the May earthquake, the US Geological Survey said.

There were no immediate reports of deaths, injuries or damage, an official at the Sichuan Seismological Bureau, who would only give his surname as Chen, told AFP.

The tremor came as China's President Hu Jintao visited neighbouring areas in Sichuan hit by the devastating May earthquake, although it was unclear whether he had already left the province by the time Monday's quake struck.

China's state television CCTV reported that Hu had visited several towns in Sichuan from Saturday to Monday, including Mianyang.

A spokeswoman for the Sichuan government said she was unaware of whether Hu had already left, and China's foreign ministry was not immediately available for comment.

The tremor was felt in Chongqing, a city roughly 300 kilometres away from the epicentre of the quake, a resident there told AFP.

A local government spokesman in Jiangyou, another town near the epicentre, said he ran out of his office when he felt the tremor.

"I was in the office then and felt the building shaking, and we ran out of the room immediately," said the spokesman, also surnamed Chen.

A receptionist at Jiangyou Hotel, who gave her surname as Wang, also felt the quake.

"I was sitting in a chair and it started to shake, I started to run out but it suddenly stopped," she said.

Ma Zhenquan, an official at the disaster relief office of Qingchuan county that was also affected said information was still being gathered about casualties and damage.

"The quake was located in a mountainous area," Ma said.

"We need some time to gather the information because the villages are too far away."

The latest quake occurred after two other tremors, with magnitudes of 4.3 and 4.9, hit the neighbouring province of Yunnan on Friday, affecting 95,000 people and leaving 19 people injured.

The 8.0-magnitude Sichuan earthquake on May 12 was the worst in a generation in China, flattening entire towns and leaving more than 87,000 people dead or missing.