U.S. President Donald Trump is thanking the men and women who died in service to the United States.

In the first of two tweets Trump sent out on Monday, he says: “Today we remember the men and women who made the ultimate sacrifice in serving. Thank you, God bless your families & God bless the USA!”

In the second, Trump says: “I look forward to paying my respects to our brave men and women on this Memorial Day at Arlington National Cemetery later this morning.”

The president is to deliver his first Memorial Day address and lay a wreath at the cemetery, the final resting place for many U.S. military members and others who have served the country.

Trump had also tweeted early Monday morning about North Korea shooting a ballistic missile into waters near Japan and an attack on "the Fake News Media."

Trump, however had yet to tweet any acknowledgement or condolences for the two vicitms of a fatal stabbing, which has been dubbed an attack of domestic terrorism, on a train in Portland, Oregon. Trump tweeted twenty times since the deadly attack, before tweeting his condolences on Monday.

The story, which has gripped the U.S., involved two men trying to stop the assailant from harassing two women who appeared to be Muslims. The man, Jeremy Joseph Christian had been yelling anti-Muslim slurs at two women, one of whom was wearing a hijab, before fatally stabbing two men who tried to intervene.

Trump had also tweeted on Sunday that many of the leaks from the White House were "fake news," following reports his son-in-law Jared Kushner tried to set up a secret channel of communications with Moscow before Trump took office.

Trump returned to the White House after a nine-day trip to the Middle East and Europe that ended on Saturday to face more questions about alleged communications between Kushner and Russia's ambassador to Washington.

"It is my opinion that many of the leaks coming out of the White House are fabricated lies made up by the #FakeNews media," Trump wrote in a series of Twitter posts on Sunday.

Kushner, who is married to Trump's daughter Ivanka, had contact with Moscow in December about opening a secret back channel of communications, according to news reports published while Trump was away on his trip.

Kushner had at least three previously undisclosed contacts with the Russian ambassador to the United States during and after the 2016 presidential campaign, seven current and former U.S. officials told Reuters.

The top Democrat on the House intelligence committee said that it’s “obviously very concerning” that a key Trump campaign figure was possibly seeking secret communications with a country that intelligence experts say intervened in the 2016 election.

Rep. Adam Schiff of California said the government needed to “get to the bottom” of the matter and urged a review of Kushner’s security clearance “to find out whether he was truthful.”

“If not, then there’s no way he can maintain that kind of a clearance,” Schiff said.

Sen. Cory Booker, D-N.J., a member of the Foreign Relations Committee, described the latest allegations involving Kushner as “serious” and called for a thorough investigation.

He needs to answer for what was happening at the time,” Booker said. “What’s worrying me are the patterns we’re seeing. So one is this administration not talking about our values, cozying up to authoritarian leaders. And the other pattern we have is just a continuous drumbeat of inappropriate contacts with the Russians.”

Lawyers for Kushner said he was willing to talk with federal and congressional investigators about his foreign contacts and his work on the Trump campaign.

"Whenever you see the words 'sources say' in the fake news media, and they don't mention names ... it is very possible that those sources don't exist but are made up by fake news writers. #FakeNews is the enemy!" Trump wrote.

Trump's tweets came as the media reported that the White House was preparing to establish a "war room" to combat mounting questions about ties between Russia and his presidential campaign.

Contacts between Trump associates and Russian officials during the campaign coincided with what U.S. intelligence agencies concluded was a Kremlin effort through computer hacking, fake news and propaganda to boost Trump's chances of winning the White House.