LIMA (AFP) - A powerful earthquake devastated several Peruvian cities killing at least 337 people in toppled buildings and forcing the government to declare a state of emergency on Thursday.

As many as 1,000 people were injured and tens of thousands of panicked residents flocked onto the streets fearing aftershocks, after the 7.9-magnitude quake rattled the country for two terrifying minutes late Wednesday.

The towns of Pisco, Chincha, and other localities in Peru's southern coastal region were said to be in ruins after the biggest earthquake to hit the South American nation in decades.

Buildings left standing had their windows smashed and trees were toppled.

In the coastal city of Ica, 300 kilometers (190 miles) south of Lima, the Senor de Luren church collapsed during a service, killing at least four worshippers and injuring dozens.

The nearby city of Pisco was also hit hard with many people killed in their homes as roofs caved in.

The government sent a convoy of trucks to the region carrying medical supplies, doctors and nurses.

The quake and aftershocks sparked panic in the capital, Lima, where people camped on the streets for hours after the first big tremor and most buildings were evacuated as a precaution.

Cut telephone lines were slowly reconnected in the capital but power and water services continued.

The quake struck just offshore at 6:41pm (2341 GMT) and prompted evacuations along the Pacific coast because of fears of a tsunami. The Pacific Tsunami Warning Center later lifted its warnings.

The government declared its highest state of emergency as authorities grappled with collapsed buildings and cut power and telephone lines.

Hospitals around the country were put on high alert amid predictions the death toll would rise and the health ministry made an emergency appeal for blood donations.

A strike launched Wednesday by some health workers was called off so all doctors and nurses could help with the emergency and the authorities closed schools to avoid the risk of new casualties in the quake ruins.

President Alan Garcia went on national television to appeal for calm.

"Fortunately, the number of dead is not high for a quake of this power," he said. "Thanks to God almighty, it has not been as serious as in the past."

Peru has long lived in fear of a repeat of a 1970 earthquake killed 70,000 people, many of whom perished in the mountain city of Huaraz which was buried by a mudslide.

A 2001 earthquake in the southern Peruvian state of Arequipa killed 75 people and destroyed 25,000 homes.

The quake measured 7.9 on the moment magnitude scale, according to the US Geological Survey (USGS). Peruvian authorities said it measured 7.7 on the open-ended Richter scale.

The epicentre was offshore about 148 kilometers (92 miles) southwest of Lima at a depth of 40 kilometers (25 miles), according to USGS.

A second 5.9 magnitude earthquake struck about an hour and 20 minutes later near the same location and at a depth of 10 kilometers (0.6 miles).

Late Wednesday, the country was rattled by a 5.6 magnitude aftershock near the coast of central Peru.

Nearly 40 minutes after the first quake, tsunami warnings were issued for the 11 countries on the Pacific south of the United States, especially Chile, Peru, Ecuador and Colombia.

The Colombian government evacuated buildings in the port cities of Tumaco, Buenaventura and Bahia Solano. Peruvian authorities told residents of La Punta district, in the port of Callao which serves Lima, to leave their homes.

Although a subsequent advisory from the center stated that sea level and subsurface instruments indicated a tsunami had been generated by the quake, the warning was cancelled at 0209 GMT.