BEIJING - China's Ministry of Public Security has warned traffic police to stand alert against "safety loopholes" on road after a bus accident killed at least 16 people Monday.

The ministry ordered local police to beef up patrols on highway and major arteries, and launch thorough safety check of vehicles at tourist sites.

A sleeper coach carrying 35 people plunged into a river dozens of meters below a highway in Xiangshan county of Yichang city in Central China's Hubei province Saturday afternoon.

Fourteen people were killed at the scene and two died later in hospital, while 19 others were injured, including eight in serious condition.

Most of the victims and injured were families on a picnic trip, according to local authorities.

The ministry has dispatched a work team to investigate the accident.

China's National Day holiday and the Spring Festival holiday are the only two seven-day holidays for the public and peak seasons for travelling.