Residents of Tibet's regional capital Lhasa have donated so much tsamba to the quake-stricken Yushu in the neighboring Qinghai Province over the past week that many stores selling the Tibetan staple food have run out of it.

Many tsamba shops on Ramoche Street, which is named after the famous Ramoche Monastery and is a major grocery street for Tibetans, have closed as their stocks had completely sold out.

Gurum Tsamba, the largest tsamba shop on the street, was the only one that remained open Saturday.

Shop assistant Tashi said daily sales soared from 10,000 to 40,000 kilograms after a 7.1-magnitude quake shook the Tibetan Autonomous Prefecture of Yushu on April 14..

"Many corporate donors have placed big orders directly with the mills, so we have to wait longer to get supplies," he said. The nearest mill that makes tsamba is in the outer counties about an hour's drive away from Lhasa's city center.

Tashi said his store offered a 4-percent discount for every kilogram of tsamba bought for donation. "This is the least we can do for those people in the quake-hit areas."

Tsamba is a unique Tibetan staple food made of highland barley flour. It is the ideal food for the tough plateau environment of Tibet and Qinghai, because it's easy to cook, high in calories and provides energy for a longer time than other food.

Tibet is the world's largest highland barley production base, with an annual output of 550,000 to 600,000 tonnes.

The donation fervor has also caused a local shortage of Tibetan tea bricks, an essential ingredient for the famous Tibetan yak butter tea.

"Many people buy dozens of tea bricks and mail them to Qinghai," said Lhadron, who owns a tea shop on Ramoche Street.

Like all other shop owners, Lhadron had not raised her prices. "The price we purchase it from the tea factories has also remained unchanged," she said.

Tibet has so far donated nearly 700 tonnes of relief supplies, including food, water and medicine for high altitude illnesses, to Yushu, said Xu Qiaofei, a civil affairs official with the regional government.

Meanwhile, cash donations have reached 11 million yuan (1.6 million U.S. dollars).