The UN Security Council on Thursday denied international port access to four North Korean ships suspected of carrying or having transported goods banned by international sanctions targeting Pyongyang, diplomats told AFP.

The ban of the four vessels -- the Ul Ji Bong 6, Rung Ra 2, Sam Jong 2 and Rye Song Gang 1 -- was requested by the United States along with measures targeting ships registered in other countries, they said on condition of anonymity. 

But China only agreed to target the four North Korean ships, diplomats said, as part of the bid to curb Pyongyang's missile and nuclear programs.