President Trump says he expects to meet with Russian President Vladmir Putin on the sidelines of an upcoming summit during his first official visit to Asia.

Mr. Trump told reporters on Air Force One en route to Japan on Sunday he "will want Putin's help" in dealing with the North Korea crisis, adding that he'll be meeting with a number of world leaders to discuss how to pressure North Korea.

The two leaders could cross paths twice during the president's lengthy Asia trip: first at a summit in Vietnam and later in the Philippines. They previously met along the sidelines of the G-20 summit in Hamburg, Germany, this summer where the two reportedly discussed election hacking and the North Korean regime.

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Isaac Stone Fish, a senior fellow at the Asia Society's Center on U.S.-China Relations, said that on one hand, it is helpful for Mr. Trump to meet with Putin to discuss Syria and North Korea.

"Russia is, while not an ally of North Korea, a fairly important trading partner for the country and it is helpful to have Russia on board, for the administration," he said. "On the other hand … there is so much worry about Trump's relationship with Russia. And where things are domestically, it's not good optics for him to necessarily do so."

Putin and Mr. Trump's meeting would come amid continuing probes into Russian meddling in the 2016 U.S. election and any ties to the Trump campaign.

Before departing from the White House, Mr. Trump told reporters he doesn't "remember much" about a March 2016 meeting with George Papadapolous, a former campaign foreign policy adviser who is now front and center in special counsel Robert Mueller's investigation into Russian election meddling.

"It was a very unimportant meeting. It took place a long time ago. I don't remember much about it," said Mr. Trump.

U.S. President Donald Trump and first lady Melania Trump arrive on Air Force One at U.S. Air Force Yokota base in Fussa, on the outskirts of Tokyo, Japan, November 5, 2017. JONATHAN ERNST/REUTERS

Papadopoulos had pleaded guilty to lying to the FBI about the nature of his interactions with "foreign nationals" who he thought had close connections to senior Russian government officials.

The White House says Papadopoulos was merely a campaign "volunteer" whose claims shouldn't be taken seriously.

Papadopoulos' charge was just one of three that have since come down in the special counsel's probe -- Mr. Trump's former campaign chairman Paul Manafort and Rick Gates, Manafort's former business associate, were also indicted by a federal grand jury last week.

The indictment against Manafort and Gates includes contains 12 counts including conspiracy to launder money, conspiracy against the U.S., unregistered agent of a foreign principal, false and misleading statements surrounding the Foreign Agents Registration Act (FARA), false statements and seven counts of failure to file reports of foreign bank and financial accounts.

The two pleaded not guilty to the charges and will return to federal court on Monday.