The UK is "absolutely determined" to make North Korea "see sense" over its nuclear weapons testing, Boris Johnson said as he pushed for tougher action at talks in Brussels.
Progress is being made on calls for China to use its influence on Pyongyang, but there is "more to be done", the Foreign Secretary said.
Foreign Office sources said Mr Johnson had succeeded in "getting tough language" in the formal agreement at the meeting with his European Union counterparts after warning they must not be divided in their response.
In the face of calls from some EU ministers for dialogue with Kim Jong-un's regime, Mr Johnson pushed for Brussels not to engage until "credible and authentic progress" is made to denuclearise, they added.
North Korea raised the stakes earlier this month with a test launch of an intercontinental ballistic missile that its defence officials said marked the "final step" in creating a "confident and powerful nuclear state that can strike anywhere on earth".
Speaking in Brussels, Mr Johnson said: "We remain absolutely determined to try to get the North Koreans to see sense and to continue to put pressure on the regime in Pyongyang and we think the best way to do that is, of course, is to put pressure on the Chinese and we are seeing some progress there but more to be done."