Top dignitaries set to convene, with a focus on North Korea The summit occurs as North Korea is in talks with South Korea over Olympics.

 -- Top dignitaries ranging from foreign ministers to ambassadors will convene in Vancouver, Canada, Tuesday to discuss the ongoing diplomatic efforts to contain North Korea’s nuclear and ballistic missile programs.

The summit, known as the “Vancouver Group,” is being held as North Korea and South Korea continue historic talks at their border about how North Korea will participate in the Pyeongchang Winter Olympics in South Korea in February.

The Vancouver Group was announced last month, prior to the development of North and South Korea’s Olympic talks. It is being co-hosted by U.S. Secretary of State Rex Tillerson and his Canadian counterpart, Minister of Foreign Affairs Chrystia Freeland.

Attendees include the foreign ministers for the United Nations Command Sending States –- the countries that provided troops and supplies to UN forces to defend South Korea –- as well as allies like South Korea, Japan, Sweden and India.

“The meeting will bring together nations from across the globe to demonstrate international solidarity against North Korea’s dangerous and illegal nuclear and ballistic missile programs,” U.S. State Department spokeswoman Heather Nauert said in a press release last week. “Discussions will focus on advancing and strengthening diplomatic efforts toward a secure, prosperous and denuclearized Korean Peninsula.”

U.S. Secretary of Defense James Mattis was scheduled to attend a so-called welcome dinner with Tillerson, but is not expected to attend Tuesday’s summit. The Pentagon said Thursday that Mattis was attending the dinner “in support of Secretary Tillerson,” demonstrating a “comprehensive approach” to North Korea.

Noticeably absent from the summit will be representatives from China and Russia. According to U.S. Under Secretary of State Steve Goldstein, Canada and the U.S. jointly agreed to not invite those nations.

Brian Hook, the U.S. State Department’s policy planning staff director, said the U.S. has been “in discussions” with China and Russia leading up to the Vancouver Group and will provide them a “readout” at the summit’s conclusion.

China’s foreign ministry spokesman criticized the summit last week, saying, “It will only create divisions within the international community and harm joint efforts to appropriately resolve the Korean Peninsula nuclear issue,” according to Reuters.

But Hook defended their absence, saying the two countries weren’t UN Command Sending States during the Korean War. He also pushed back on the charge that not including them would hinder global efforts to curb North Korea’s nuclear and ballistic missile programs.

“This is not an alternative to everything that we are doing,” Hook said of the summit, adding that China is “working with us” and “has the same policy goal.”

Just last week, the White House released a statement saying China was “sharply reducing its trade with North Korea” –- an action that supported “the United States-led global effort to apply maximum pressure until the North Korean regime ends its illicit programs, changes its behavior, and moves toward denuclearization of the Korean Peninsula.”

The Trump administration has only recently been more complimentary toward China. In late December, President Trump slammed Beijing over reports that Chinese ships had been caught secretly selling oil to North Korea.

Caught RED HANDED - very disappointed that China is allowing oil to go into North Korea. There will never be a friendly solution to the North Korea problem if this continues to happen! — Donald J. Trump (@realDonaldTrump) December 28, 2017

As for the Vancouver Group, Hook said it would focus in part on how to increase pressure on North Korea, especially maritime interdiction to cut off resources and disrupt financing streams. This would include pushing the UN to name ships trading with North Korea to ban them from entering ports.

Tillerson told reporters in December the global pressure campaign “is intended to lead to talks,” but “we can’t talk unless North Korea is ready to talk, and I think, as we’ve indicated, we’re waiting for them to indicate a readiness to talk.”

In a statement about Trump’s call with South Korean President Moon Jae-In last Wednesday, the White House said the president “expressed his openness to holding talks between the United States and North Korea at the appropriate time, under the right circumstances.”

The U.S. has also expressed support for the bilateral discussions between North Korea and South Korea regarding the Winter Olympics.

In a continuation of those conversations this week, the two countries agreed that the North would send a 140-member orchestra, according to the head of South Korea’s delegation Lee Woo-sung.

The two Koreas may even march under a joint “unification flag” during the opening ceremony and field a joint women’s ice hockey team, the Associated Press reported citing a South Korean official.

North and South Korea will meet with the International Olympic Committee in Switzerland on Saturday.

ABC News' Conor Finnegan in Washington, DC and Hakyung Kate Lee in Seoul contributed to this report.