Beijing,  Four people were killed and 14 others injured after a powerful earthquake measuring 6.1 on the Richter scale jolted the city of Ya'an in China's Sichuan province, authorities have confirmed.

The earthquake struck Lushan county at 5 p.m. on Wednesday, according to the China Earthquake Networks Center (CENC).

The epicentre, with a depth of 17 km, was monitored at 30.4 degrees north latitude and 102.9 degrees east longitude, Xinhua news agency quoted the CENC said as saying.

The temblor was followed by a 4.5-magnitude aftershock at 5.03 p.m. in Baoxing county.

The casualties were reported in Baoxing County, the city's earthquake relief headquarters said, adding that the four people who died were hit by falling rocks, while the injured have been sent to hospital for treatment.

Telecommunication in parts of the two counties was damaged due to the quake, but some optical cables have been restored after emergency repairs.

Ya'an has activated the second-highest level of emergency response for the earthquake and is conducting damage assessments.

More than 4,500 people from emergency rescue, the armed police, the fire department, the medical sector and other departments were dispatched to the earthquake-hit areas to search for and rescue the injured, repair roads and relocate affected residents.