OTTAWA - Both China and Russia will be integral to securing peace on the Korean peninsula, Prime Minister Justin Trudeau conceded Monday even as he defended the decision to leave the two countries out of this week's international gathering on the perils posed by North Korea.

Trudeau made the remarks after Russia became the latest to slam the meeting - taking place Tuesday in Vancouver and co-hosted by Canada and the U.S. - as a threat to peace efforts. China, meanwhile, has already derided as “Cold War thinking” the involvement of only those allies that supported South Korea during the Korean War.

“There are always going to be different venues and different groupings happening, and I think a diversity of approaches is better than picking one lane and deciding that this is going to be the way it happens,” Trudeau said in an interview with The Canadian Press.

“This is an opportunity to gather together a group of nations that are historically linked through the Korean War that will be another piece, we certainly hope and feel, in the path towards resolving the conflict.”

But Trudeau also acknowledged that any successful resolution will ultimately need to include China and Russia, both of which he called “important partners” in resolving one of the world's greatest threats to peace.

Foreign Affairs Minister Chrystia Freeland and U.S. Secretary of State Rex Tillerson last month announced plans to co-host the Vancouver meeting in response to growing concerns about North Korea's nuclear and missile programs.

The participating countries will put a heavy emphasis on finding ways to crack down on the many smuggling and money-laundering schemes that Pyongyang has employed to sidestep sanctions and pay for its nuclear program.

U.S. officials have said the discussions will include whether to start intercepting North Korean shipping, which is certain to spark anger and threats from Pyongyang and could involve Canadian warships.

Underlining the military backdrop, Defence Minister Harjit Sajjan and U.S. Defense Secretary James Mattis were scheduled to attend a dinner with Freeland and Tillerson on Monday night in advance of Tuesday's gathering.

The meeting has sparked plenty of condemnation, most recently from Russia, whose foreign minister didn't pull his punches Monday in a two-hour news conference.

“We openly said that we think this meeting is harmful,” Sergey Lavrov said, echoing earlier sentiments from the Chinese government.

U.S. officials have suggested that while not invited, Russia and China were generally supportive of the decision to hold a meeting in Vancouver. Lavrov described such assertions as “an outright lie.”

He also questioned the list of countries invited to attend, all of which contributed troops and equipment to the UN force that fought against the North Koreans, Chinese and Russians during the Korean War from 1950 to 1953.

“When we found out about this meeting, we asked: 'Why do you need all those countries together? Greece, Belgium, Colombia, Luxembourg. What do they have to do with the Korean peninsula today?”'

North and South Korean officials, meanwhile, have held their first talks in several years, fuelling fresh hope that a diplomatic solution to the crisis is still within reach.

But while Canada and the U.S. have welcomed the Korean discussions, American officials have said they won't change the agenda of the Vancouver meeting or consider a short-term easing of sanctions.

NDP foreign affairs critic Helene Laverdiere called on the Trudeau government to push for diplomacy with North Korea, particularly in the face of the Trump administration's “dangerously bellicose rhetoric.”

“It is more important than ever for the Canadian government to chart a very different course,” Laverdiere said, “and assert to governments around the world that diplomacy is paramount, even when economic sanctions are underway.”