Nations tracking the Democratic People's Republic of Korea's (DPRK) ships should muster "ample evidence and proper cause" before seeking to check their cargo, China said yesterday, denying any direct knowledge of a DPRK vessel passing near its coast.

China backed a UN Security Council resolution condemning the DPRK's nuclear test on May 25 and calling on nations to enforce a ban on its arm exports. But China has also warned against enforced boarding of DPRK vessels, and Foreign Ministry spokesman Qin Gang stressed that caution.

"This is a complex and sensitive issue," Qin told a news conference when asked about enforcing the resolution.