BEIJING -- The Ministry of Emergency Management has required local governments to be on high alert for flood-triggered geological disasters and issue timely warning information and safety instructions.

The requirement came after 17 people were initially confirmed missing after a rock collapse took place at around 12:44 pm Wednesday at a section of the Chengdu-Kunming railway in Ganluo county, Sichuan province.

A work team was immediately dispatched by the ministry to instruct on-site rescue and relief. All-out efforts must be made to search and rescue the missing, sources with the ministry said Thursday.

The monitoring of mountain or slope displacement must also be enhanced to prevent secondary disasters from occurring and ensure the safety of all relief workers, they said.

Because of heavy rainfall, some places in China have become vulnerable to mountain torrents, rock collapse and mudslides.

Local governments and relevant departments should monitor high-risk regions, help people evacuate and promptly issue warning and security instructions, said the ministry.