BEIJING, May 20 (UPI) -- Workers located a man who survived eight days after an earthquake in China's Sichuan province that claimed more than 40,000 lives, officials said Tuesday.

Rescue crews extracted Ma Yuanjiang after spending 30 hours of digging through the rubble left by last week's earthquake, The Daily Telegraph reported.

Ma was discovered Sunday as the rescuers reached and saved a co-worker, officials said. Ma, who spent 139 hours trapped beneath the second floor of his office building, survived on sweetened water rescue workers fed to him through a straw.

The Chinese government said the official death toll from the earthquake has risen to 40,075, with more than 25,000 people missing, the British newspaper said. Another quarter-million people were injured.

An aftershock warning by the Sichuan government Tuesday prompted tens of thousands of residents across the region to run for cover.

Sichuan province faced a threat of a powerful aftershock. The seismological bureau in Chengdu said a 6-to-7 Richter aftershock could rock the Wenchuan epicenter area, and urged the local government and people to be prepared for emergencies, Xinhua, China (OTCBB:XHUA)'s state-run news agency, said.

China has undertaken a massive relief effort that includes tens of thousands of rescue teams assisted by more than 110,000 people, including police officers and soldiers.

After approving foreign rescue teams -- including units from Japan, Russia, South Korea and Singapore -- to aid in its relief effort, China agreed to receive foreign medical teams, Xinhua said.