GENEVA (AFP) - US Secretary of State John Kerry and his Russian counterpart Sergei Lavrov condemned North Korea's latest nuclear test on Friday (Sept 9) and said it would be referred to the United Nations.

Appearing with Mr Lavrov before the start of talks on the crisis in Syria, Mr Kerry said he had also spoken to his Japanese and South Korean colleagues and had had a "serious conversation" about the incident.

Russia, the United States, China, Japan, South Korea lead the international response to North Korea's banned nuclear weapons program as parties to the stalled "Six Party Talks" process.

"We are seriously concerned and the resolutions of the Security Council must be strictly implemented and we must send this message very strongly," Mr Lavrov said.

The Russian foreign minister said he would also speak to his Japanese counterpart later in the day.

"Obviously Japan and South Korea, particularly, are deeply concerned because of the neighborhood," Mr Kerry said. "But I think it's fair to say China, Russia and the United States, everybody shares concerns about it.

"We're trying to monitor to precisely find out what took place... and we will certainly be discussing this in the context of the United Nations, for sure."