(CNN) - In his first public appearance since Tuesday -- amid a 27-day government shutdown and 24 hours after the death of four Americans in Syria -- President Donald Trump delivered a meandering speech at the Pentagon on Thursday.
Trump began by offering condolences to the families of four Americans killed in Wednesday's suicide blast in Syria -- the first time he has acknowledged the attack since it happened.
"I want to take a moment to express my deepest condolences to the families of the brave American heroes who laid down their lives yesterday in selfless service to our nation. These are great people, great, great people. We will never forget their noble and immortal sacrifice," Trump said.
ISIS has claimed responsibility for a deadly explosion that killed four Americans and at least 10 other people in the Syrian city of Manbij on Wednesday.
The attack came after the White House announced last month that the US would be pulling troops from Syria, which led to the resignation of Defense Secretary James Mattis.
Against the backdrop of a partial government shutdown stemming from disagreements over funding for a US-Mexico border wall, Trump pivoted from the condolences to speaking about the need for a border wall through the lens of national security.
"This morning I also would like to briefly address another matter of critical national security -- the humanitarian and security crisis at our southern border. Without a strong border, America's defenseless, vulnerable and unprotected," Trump said.
The President thanked the military for its assistance on the border amid earlier migrant caravans, adding that thousands of migrants are currently moving toward the US in caravans.
"We don't know who they are, where they're from -- nothing," Trump said. "We need strong borders. We need strong barriers and walls. Nothing else is going to work," he continued, adding that a border wall "should have been done by other Presidents."
Trump, during his Pentagon speech, went on to admonish Democratic "fringe" party members, who equated to "the radical left", for a lack of progress toward reopening the federal government amid negotiations surrounding the border wall.
"While many Democrats in the House and Senate would like to make a deal, (House) Speaker (Nancy) Pelosi will not let them negotiate. The party has been hijacked by the open borders fringe within the party. The radical left becoming the radical Democrats," Trump said.
Though Pelosi as the leader of her party is who Trump needs to negotiate with, there's no evidence she's worked to block any members from talking to the White House.
Trump also found a way during his speech which was billed as focusing on missile defense to confirm his support for the North Atlantic Treaty Organization, following a New York Times report outlining his distaste for the international group.
"We cannot be the fools for others. We cannot be. We don't want to be called that and I will tell you for many years behind your backs ... that is what they were saying. So there's a big difference. We're going to be with NATO 100% but as I told the countries, you have to step up," he said.
The President has frequently called on nations in the alliance to pay a larger share of their defense spending.
"They're starting to step up," he added.
Trump also touted building a missile defense capability that "can detect and destroy any missile launching against the United States, anywhere, anytime, any place."
He said the review prioritized the need for developing new technology, obtaining new interceptors and radars, improving missile detection systems, emphasizing space missile detection, "fair burden sharing" with US allies and "removing bureaucratic obstacles" from deploying the new technologies.
And the President strongly hinted that his administration would increase the defense budget again next year.
"You're only doing that because I gave you the greatest and biggest budget in our history and I've now done it two times and I'd hate to tell the rest of the world but I'm about to do it three times," Trump told the audience following an opening round of applause.
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