New cave-ins on Monday have set back efforts to repair a main highway in Sichuan Province that mudslides closed on Sunday, police said.

State Highway 213, which links Sichuan with the provinces of Gansu, to its north, and Yunnan, to its south, was referred to as a "lifeline" by rescue workers following the devastating 2008 Wenchuan earthquake.

The highway was a vital channel for getting aid and supplies to the county's town of Yingxiu, the quake's epicenter, in Sichuan

Downpours on Monday morning triggered new cave-ins at the Luoquanwan Bridge section of the highway, which greatly hindered repair work, said Fan Zhenggang, deputy chief of the Public Security Bureau of Aba Tibetan and Qiang Autonomous Prefecture which administers Wenchuan.

The highway will probably remain closed for quite some time, Fan said.

Since Saturday, heavy downpours have wreaked havoc in Sichuan.

Four people were killed and eight missing in floods and mudslides as of 4 p.m. Monday, according to the provincial Flood Control and Drought Relief Headquarters.

Two of the four were electrocuted to death while walking in water in the provincial capital Chengdu.

More than 3,000 people have been relocated over the last three days, according to headquarters.

Direct economic losses currently stand at 200 million yuan (31 million U.S. dollars).

In the Aba Prefecture, 81 people who had been stranded on a bridge after both ends of it were washed out, were rescued Monday afternoon.