As top diplomats from 20 countries met in the Canadian city of Vancouver to discuss the North Korea crisis, Japanese Foreign Minister Taro Kono pushed for continued pressure on Pyongyang, saying that the world should not be blinded by Pyongyang’s recent “charm offensive”.

The meeting on Korean peninsula security was held on Tuesday and co-hosted by the US and Canada. US Secretary of State Rex Tillerson, South Korean Foreign Minister Kang Kyung-wha and Canadian Foreign Minister Chrystia Freeland were present, the BBC reported.

China and Russia, two of Pyongyang’s biggest allies, were not invited. Both countries have been accused of not putting enough pressure on North Korea to stop it from developing its nuclear ambitions.

The two Koreas recently held formal bilateral talks for the first time in more than two years, using the opening offered by next month’s Winter Olympics in South Korea.

Japanese Foreign Minister Kono called the North’s newfound receptiveness to dialogue an attempt to gain time for weapons development, asserting that the country’s relentless pursuit of its nuclear and missile programmes must not be ignored.

He warned against being swayed by North Korea’s “charm offensive”.

“The international community should unite behind the goal of complete, verifiable and irreversible denuclearization of the Korean Peninsula”, Kono said.

North Korea has in the past two years rapidly advanced its nuclear and conventional weapons programmes, despite increasing international sanctions.

Its latest ballistic test, on November 28, sparked a new series of fresh sanctions from the UN, which targeted petrol shipments and travel.

The US echoed Kono remarks, with Tillerson calling for an increase in pressure on Pyongyang to the point where it “must come to the table for credible negotiations”.

South Korean Foreign Minister Kang Kyung-wha told the meeting she believed recent sanctions and pressure had a part to play in North Korea’s recent willingness for talks.

“Indeed the concerted efforts of the international community has begun to bear fruit,” she said.

In their final joint statement, the 20 nations said they would consider imposing tougher sanctions on Pyongyang going beyond those required by UN Security Council resolutions.

Beijing dismissed the meeting as “illegitimate”. Chinese Foreign Ministry spokesman Lu Kang said: “The most important relevant parties of the Korean peninsula issue haven’t taken part in the meeting so I don’t think the meeting is legal or representative.”