BEIJING, April 20 (Xinhua) -- China's Ministry of Transport on Sunday asked related authorities to step up safety management and remain alerted after a sunken South Korean ferry left hundreds dead or missing.

Local transport authorities should draw a lesson from the tragedy and intensify measures during the coming May Day holiday to ensure the safety of ferries, the ministry said in a notice.

Water traffic is expected to boom with mounting tourists in the three-day May Day holiday starting from May 1.