NING'ER, Yunnan Province, June 5 (Xinhua) -- At least 329 people were hospitalized after an earthquake measuring 6.4 on the Richter scale hit Pu'er city in southwest China's Yunnan Province early on Sunday, the local government said on Tuesday.

By 11:00 p.m. Monday, the quake and its aftershocks had killed three people, including a four-year-old boy, and caused 28 fatal injuries in the Ning'er Autonomous County of Hani and Yi nationalities, one of the worst hit areas, the county's quake relief headquarters said.

The county, famed for its tea, has been rocked by 1,253 aftershocks, 29 of which measured more than 3.0 on the Richter scale with the largest registering 5.1. Experts have warned of the possibility of more.

The quake had displaced at least 180,000 people in Pu'er city by Monday night, incurring direct economic losses of 2.5 billion yuan (about 327 million U.S. dollars).

In Ning'er county alone, nearly 65,000 people had been evacuated from their damaged homes to live in tents or public places. The county government estimated its economic losses at 1.4billion yuan (180 million U.S. dollars).

At least 2,000 army troops and armed police have joined the rescue work in the county.

More than 5,000 tents have been put up at the central square in the county to accommodate the evacuees. But the county needs an additional 15,000 to ensure one for every homeless family, said Ma Bin, head of the civil affairs bureau.

About 30 volunteers are helping officials deliver bottled water, food, quilts and other relief material to the evacuees on Tuesday.

"This will be my last memory of Ning'er," said Yao Yiping, a college graduate from Shanghai whose two-year term as a poverty reduction coordinator in the county will end next month.

"I'll go back to Shanghai when all this is over," said Yao, who herself found lodging in a tent after her dormitory was destroyed in the quake.