WHITE HOUSE - U.S. President Donald Trump and Russian President Vladimir Putin shook hands and exchanged a few words Friday at the Asia Pacific Economic Cooperation summit dinner in Vietnam.

The brief encounter came after the White House attempted Friday to put to rest speculation that Trump might hold talks with Putin on the sidelines of the summit. White House Press Secretary Sarah Huckabee Sanders said the two leaders may have a brief chat, but will have no substantive talks.

White House: Trump, Putin Shake Hands at APEC Summit but No Sidelines Talk

"Regarding a Putin meeting, there was never a meeting confirmed, and there will not be one that takes place due to scheduling conflicts on both sides," Sanders said in a statement issued to reporters. "There is no formal meeting or anything scheduled for them.

White House: Trump, Putin Shake Hands at APEC Summit but No Sidelines Talk

The statement did, however, hold open the possibility that the two leaders might have an informal conversation while they are both in Danang for the summit proceedings.

White House: Trump, Putin Shake Hands at APEC Summit but No Sidelines Talk

"They’re going to be in the same place. Are they going to bump into each other and say hello? Certainly possible and likely," Huckabee Sanders wrote. "But in terms of a scheduled, formal meeting, there’s not one on the calendar and we don’t anticipate that there will be one."

Russian news agency RIA Novosti on Friday seemed to contradict the White House, holding out hope a substantive meeting might still take place. A one-line bulletin reported, "Kremlin Says Possible Meeting Between Putin and Trump at APEC Summit Still Being Worked On."

The Russian side had earlier issued seemingly conflicting views about the possibility of a meeting. Kremlin aide Yury Ushakov told Russian news agencies that the two leaders would hold talks, but Reuters quoted Putin spokesman Dmitry Peskov as moderating that statement, saying only that the possibility of a meeting was being discussed.

While en route to Danang on Friday, U.S. Secretary of State Rex Tillerson said he had seen the Russian reports but said nothing had been agreed to.

In a brief exchange, Tillerson said the United States wants progress on a number of issues, and there would be no point to hold a meeting if they didn’t think they would get the progress.

A day earlier, Tillerson had acknowledged that Moscow and Washington were working behind the scenes on a "number of difficult areas." But he questioned whether this would be the right time for a follow-up to the first Trump-Putin meeting at the G-20 summit in Germany last July.

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That meeting in Hamburg lasted more than two hours, more than twice as long as scheduled. Trump was reported to have pressed Putin at that meeting on the question of alleged Russian meddling in U.S. elections. Later in the day, the two men were reported to have spoken again informally during a dinner for G-20 leaders, with only a Russian interpreter present.

Since then, however, ties between Moscow and Washington have deteriorated. In August, Trump grudgingly approved new congressionally mandated sanctions against Russia. The Kremlin responded by ordering Washington to substantially cut its diplomatic staff in Russia.

Trump himself mentioned the possibility of a follow-up meeting last weekend, telling reporters aboard Air Force One that he expected to meet Putin in Vietnam to ask for help in reining in North Korea’s nuclear weapons development. He made a similar comment Thursday in Beijing after meeting with China’s President Xi Jinping.

Tillerson said officials from the two countries also are discussing conflicts in Syria and elsewhere in the Middle East, while Trump also said that Russia’s interference in the 2016 U.S. presidential election also remains on the table for discussion.

Several scholars of U.S.- Russia relations are leery of direct Putin-Trump talks at this delicate time in the relationship.

Kremlin critic Andrei Piontkovsky, a visiting fellow at the Hudson Institute in Washington, says Putin stands to gain much more from the meeting than Trump.

"It would be better if the United States and Russia have good relations, but the fact is, Putin is challenging the U.S. everywhere in the world, including on their own turf, and Trump doesn’t seem to consider that is hostile to western values, democracy and human rights," Piontkovsky told VOA. "It’s very strange because Trump declines to notice these worrisome facts."

Piontkovsky considers it foolish to ask for the Kremlin’s help in lessening the North Korean threat.

"That ignores the fact that the tremendous progress of the North Korean nuclear program is enabled by Russian help," Piontkovsky argued. "Putin is much more an enthusiastic supporter of Kim Jung Un than Xi Jinping. He demands that the U.S. reconcile itself with the idea of a new nuclear power."