Trump promises to do 'what's right for the world' in containing North Korea

U.S. President Donald Trump admitted on Wednesday he wants a tougher stance on North Korea than some of his advisers, while denouncing as "fake" an NBC report earlier in the day indicating that he wanted a tenfold increase in the U.S. nuclear arsenal.

Trump made his comments to reporter questions during a photo opportunity with Prime Minister Justin Trudeau, as the U.S. and Canada are engaged in talks about renegotiating the North American Free Trade Agreement.

With regard to North Korea, which has tested several missiles in the past year as it seeks to advance its nuclear capabilities, Trump's comments were stern but not nearly as incendiary as a series of tweets and public statements in the summer. He also refrained from mentioning Kim Jong-un by name or a derisive nickname.

Trump said he had no problem with disagreement within his administration on how to contain North Korea.

"I think that I have a little bit different attitude on North Korea than other people might have and I listen to everybody, but ultimately my attitude is the one that matters, that's the way it works," he said.

"Ultimately I will do what's best for the United States, and really, what's right for the world," Trump said at a different juncture.

• Trump, meeting with Trudeau, hints at bilateral deal with Canada

Regarding the NBC report on wanting to dramatically increase the nuclear arsenal, Trump said he's primarily concerned with the arsenal being in "tip top shape." The modernization and rehabilitation of the arsenal was "the only thing I've ever discussed," Trump contended.

"I know the capability we have, believe me, and it is awesome," he said. "It is massive."

The report said that at a July 20 briefing, Trump had questioned why the stockpile had slid from a high of 32,000 in the 1960s. NBC reported that Trump had trouble understanding why the number has been dramatically reduced through the decades.

The United States currently has about 4,000 nuclear warheads earmarked for use in its military stockpile, according to the Federation of American Scientists.

Mattis also slams report

Although U.S. presidents have modernized weapon stockpiles over the years, adding to the nuclear arsenal or building a prohibited type of weapon would likely be in violation of various treaty agreements.

MSNBC reported in 2016 that as a candidate, Trump asked a foreign policy adviser three times in a one-hour meeting why the United States could not deploy its nuclear weapons.

Soon after the photo op, Defence Secretary James Mattis released a statement denouncing the latest NBC report.

"This kind of erroneous reporting is irresponsible," Mattis said in a written statement.

Last week, NBC reported that Rex Tillerson referred to the president as a "moron" during a similar time period this summer, citing anonymous sources familiar with the situation. That report came just days after Trump took to Twitter to say that Tillerson was "wasting his time" seeking talks with the isolated regime. Today's NBC report says it was after the July meeting that officials heard Tillerson say that Trump is a "moron."

Tillerson last week publicly confirmed his loyalty to Trump, and the president said Wednesday the pair have "a very good relationship."

Trump also said the White House would be announcing its direction concerning Iran's nuclear program "very shortly."

Trump has taken aim at a multilateral nuclear deal with Iran agreed to by predecessor Barack Obama and other nations since early in his presidential campaign, and could move to decertify the deal.