Washington(CNN) The United States and Canada will co-host an international summit on the North Korean nuclear threat in Vancouver, British Columbia, on Tuesday, as tensions on the Korean Peninsula settle into a steady simmer while direct talks between the north and the south continue.

The summit comes at a critical time. But with diplomats' attentions absorbed by the delicate talks between the two neighboring countries -- which were initially focused on North Korea's participation in the upcoming Pyeongchang Winter Olympics but have since broadened -- some analysts are skeptical that much will come out of the Vancouver meetings.

"I'm sure, given the circumstances on the peninsula right now, that the attendees to that meeting will be very careful about what they say publicly," Joel Wit, of the US-Korea Institute at the Johns Hopkins School of Advanced International Studies, told reporters last week, "because I think most of them there would not want to 'upset the apple cart' in any way."

"I think whatever they do, whatever they say," said Wit, "it's going to be supportive of what the South Korean government is trying to achieve."

Still, the Trump administration is optimistic it can use Tuesday's discussions to advance its so-called "peaceful pressure" or "maximum pressure" campaign, which it believes is partly responsible for North Korea's willingness to resume conversations with South Korea.

Secretary of State Rex Tillerson and Secretary of Defense James Mattis will participate in the summit.

Tillerson's efforts on North Korea have, at times, been complicated by bellicose rhetoric from his boss, President Donald Trump.

In October, for instance, Trump tweeted that "Rex is wasting his time trying to negotiate with Little Rocket Man."

The two men have endured a rocky relationship in recent months, though Tillerson asserted in a recent CNN interview that he's learned to "better deal with" Trump, and plans to stay in his role at least through 2018.

In the same interview with CNN, Tillerson said that through his tweets, the President "has demonstrated to the world how high the stakes are."

In a news briefing on Thursday, the State Department's director of policy planning, Brian Hook, told reporters that North Korea is "starting to feel the bite" from the campaign, adding, "we think that this creates the kind of conditions that led to discussions between the North and the South about the Olympics."

Negotiators from the two countries met again at the demilitarized zone Monday and agreed to further talks.

Sanctions on the agenda

"We are going to be at this Vancouver ministerial doing an assessment of progress to date," said Hook. "We'll be discussing sanctions -- the sanctions that we have done multilaterally and unilaterally to date -- and their effectiveness, and what we can be doing in the coming year."

The United States and Canada will be joined at the summit by a group of 18 nations including South Korea and Japan.

But North Korea's largest trading partner, China, will not be participating.

"We will give them a readout of this ministerial after it's over," said Hook, "and we have been in discussions with the Chinese and the Russians leading up to this Vancouver ministerial."

"The scope of this, I think, is going to be really limited to reinforcing the UN Security Council's resolutions on the North Korean nuclear issue," says Frank Jannuzi, president and CEO of the Mansfield Foundation, which promotes US-Asian relations, "which means that the main emphasis will be on ensuring solidarity, strict sanctions enforcement."

But the forum's limited guest list could also offer an opportunity for the United States' partners to nudge the Trump administration, at least privately, toward expanding direct talks with the North Korean regime on the nuclear issue, he noted.

In an interview last week with the Wall Street Journal, Trump seemed to signal he was open to more engagement with Pyongyang, saying, "I probably have a very good relationship with Kim Jong Un."

"I think that the European powers might be emboldened a little bit (by that) to go ahead and push," Jannuzi suggested to CNN.

Neither Trump nor his White House would clarify whether the President had spoken with the North Korean leader, who he has repeatedly called "Little Rocket Man," although Trump told reporters Sunday that he had been misquoted in the interview.

But China won't be there

One area where diplomats hope to make progress Tuesday is with maritime interdiction: efforts to disrupt the flow of smuggled goods into North Korea in violation of the UN sanctions regime.

"We continue to explore all options to enhance maritime security and the ability to interdict maritime traffic -- those transporting goods to and from the DPRK that support the nuclear and missile program," Hook told reporters, adding that talks would also address ways to disrupt financial transfers to the country.

But without China's participation, critics worry the talks will be fruitless. China has been singled out for criticism by the United States, which says Beijing is not doing enough to crack down on sanctions evaders and that it has allowed the transfer of banned oil.

"Caught RED HANDED," Trump tweeted in December, "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!"

In his briefing last week, Hook said China was making progress on the issue.

"We've been very pleased that China has certainly given much fuller implementation," he said. "I think they have closed some sanctions gaps."

Jannuzi says the chances for additional action on the interdiction issue are "slim to zero," unless North Korea resumes its provocative behavior.

"I don't see any hope for the US to get support for the idea of boarding ships at sea," he told CNN last week. "The UN Security Council went as far as they were willing to go, with Chinese and Russian support, to allow nations to board ships in port, to inspect them and make sure they're complying with the UN sanctions regime."