BEIJING (AFP) - Twenty-two people were killed and more than 100 were injured after an earthquake measuring 6.1 on the Richter scale rocked southwest China on Saturday, state media reported. The tremor jolted Panzhihua City in Sichuan province, where a devastating 8.0 quake struck in May, at 4:30pm (0830 GMT), according to Xinhua news agency. Seventeen people died and about 100 were injured in Sichuan, while five were killed and 35 hurt in neighbouring Yunnan province, Xinhua said. In Sichuan, a 54-year-old man was found dead in rubble, while another was confirmed to have died when a house collapsed. Xinhua said more than 1,000 houses had been destroyed by the tremor while about 400 had cracks. Teams from the China Earthquake Administration, and the Sichuan and Yunnan provincial earthquake bureaux, were heading to the stricken region, Xinhua said. However, rescue operations had been hampered by the rugged conditions in the area as well as heavy rains. Detailed casualty figures were unavailable due to poor communication, Xinhua said. The US Geological Survey measured the quake at 5.7. The quake epicentre was about 30km southeast of Panzhihua, 161 kilometres northwest of Kunming, Yunnan's provincial capital, USGS said. Five people died in Chuxiong Prefecture in Yunnan, said Mengfu, a local official, according to Xinhua. The Yunnan Seismological Bureau said the quake and its aftershocks were also felt in Yongren county, Yunnan. "Locals in the county rushed out into the open. Cracks appeared on house walls and many windows were broken," Xinhua quoted Zheng Zhouwei, a local legislator in Yongren, as saying. The quake also shook Chengdu, Sichuan's capital, according to Xinhua, which added that many residents stayed outside after the tremor. A massive 8.0 magnitude quake hit Sichuan province on May 12, leaving nearly 70,000 dead, with about 18,000 people still missing.Meanwhile, a 5.2-magnitude earthquake struck off the northern Philippines Saturday but there were no immediate reports of casualties or damage, the US Geological Survey said. The epicentre of the tremor, which was 40km beneath the surface, hit 65 kilometres east-southeast of Legaspi on the main island of Luzon, at 8.04pm (1204 GMT). The archipelago nation, made up of more than 7,000 islands, sits on the Pacific "Ring of Fire" where continental plates collide, causing frequent seismic and volcanic activity.