BEIJING, Oct. 13 (Xinhua) -- Chinese authorities have warned of continued risk at a border area between Sichuan Province and Tibet Autonomous Region in southwest China, where a landslide struck on Thursday and blocked part of a river.

The Ministry of Emergency Management said Saturday that the possibility of another landslide is growing, after a 300-meter-long crack was spotted on the surface of the mountain where the previous landside had occurred, increasing the risk of the river being cut off again.

Evacuation of villagers nearby and deployment of disaster relief workers to the site should start immediately, the ministry said, demanding strengthened monitoring and new response plans.

The landslide happened at about 7 a.m. Thursday and led to the formation of a barrier lake near a section of the Jinsha River.

The ministry said earlier that water from the upper stream had burst through the blockade, causing the water level in the barrier lake to significantly drop and signaling eased pressure in lower reaches.

More than 21,000 people had been relocated by 2 p.m. Friday, with no reports of any casualties.