RIGA, Latvia -- Vice President Joe Biden said Tuesday that the U.S. was "absolutely, thoroughly, 100 percent committed" to NATO and that its Baltic allies should ignore Republican presidential candidate Donald Trump.

"The fact that you occasionally hear something from the presidential candidate of the other party, it's nothing that should be taken seriously," Biden said during a meeting with the leaders of Latvia, Lithuania and Estonia. He said he didn't think Trump, who has repeatedly said he'd consider making U.S. military support conditional on whether NATO members have met their financial obligations to the bloc, understood Article 5 of the alliance treaty.

It provides that an attack on one NATO member should be considered an attack on all. The vice president echoed his criticism at a speech later Tuesday to the Baltic people from the Latvian capital, Riga, saying that "despite what you hear in this heated political season," there was enduring bipartisan support for NATO.

"Don't listen to that other fellow," Biden said. "He knows not of what he speaks."

Biden said there should be "no doubt" that the U.S. had pledged its "sacred honor" to the common-defense provision. "We want you to know, we want Moscow to know, we mean what we said," the vice president added.

Trump has drawn criticism from U.S. lawmakers from both parties since he suggested in an interview with The New York Times that NATO allies could count on U.S. military aid "if they fulfill their obligations to us."

Few countries meet NATO's guideline that they spend 2 percent of gross domestic product on defense. Of the alliance's 28 members, only U.S., U.K., Estonia, Poland and Greece met that threshold last year. Every Republican and Democratic presidential candidate has supported NATO since Dwight Eisenhower stepped down from leading the alliance to run for the White House in 1952.

Trump's comments come as eastern European nations are already skittish over Russian aggression in light of the 2014 annexation of Crimea from Ukraine and the conflict that ensued. The U.S. and European Union imposed sanctions on Russian political and business interests over the move.

Lithuanian President Dalia Grybauskaite, Estonian President Toomas Hendrik Ilves and Latvian President Raimonds Vejonis said before a working lunch with Biden that they were confident in the U.S. commitment to the alliance.

White House spokesman Josh Earnest told reporters aboard Air Force One on Tuesday that it was "dangerous to raise any doubt about the U.S. commitment to our NATO allies."

The vice president's remarks "were an effort to clear up any confusion that may exist on that front. And some of that confusion may stem from some of the rhetoric that we've seen on the campaign trail," Earnest said. "And that's unfortunate."

Russia has increasingly become a hot-button issue in the U.S. presidential campaign, with Trump drawing criticism over his depiction of Russian President Vladimir Putin as a strong leader with whom he could do business. Trump has said the U.S. should scale back its role in mediating the Ukrainian conflict.

Adding to U.S.-Russia tensions, the FBI is said to have high confidence that Russia was responsible for hacking attacks on the Democratic National Committee and other Democratic-affiliated groups that led to the release of stolen emails by WikiLeaks.

From Latvia, Biden travels to Turkey, arriving today in the Turkish capital, Ankara. His visit comes as the country is still reeling from last month's coup attempt that Turkish leaders say was orchestrated by a U.S.-based cleric.

Turkish officials complained that Washington was slow to support Turkey's government at its time of greatest need, even though the U.S. had expressed support for Recep Tayyip Erdogan during the violence on July 15 that claimed 270 lives.

Biden went bearing no assurances that the United States will agree to Turkey's demand that it extradite Fethullah Gulen, who lives in Pennsylvania. Instead, he'll try to convey that America values Turkey as a key NATO ally amid signs that the U.S. and Turkish approaches to the Syrian conflict may be diverging.

Ahead of Biden's visit, the U.S. said it was considering a formal extradition request for Gulen from Turkey. But State Department spokesman Mark Toner said Tuesday that Turkey's request was for alleged crimes unrelated to the failed coup. He declined to provide details.

The U.S. was seeking further evidence from Turkey to substantiate its claim that Gulen was behind the overthrow attempt. Turkey's Justice Ministry said its officials opened talks Tuesday with a team from the Justice Department and State Department that the U.S. dispatched to Ankara ahead of Biden's arrival.

Information for this article was contributed by Justin Sink and Aaron Eglitis of Bloomberg News and by Josh Lederman and staff members of The Associated Press.

A Section on 08/24/2016