Ahead of Monday’s meeting with President Trump and European leaders, Ukrainian President Volodymyr Zelenskyy posted that he had arrived in Washington, D.C.

Notably, he expressed his gratitude toward Trump and America and said, “peace must be lasting,” noting that security guarantees and forfeiting land in the past have done little to stop Putin.

Zelenskyy said he was grateful for the invitation and “We all share a strong desire to end this war quickly and reliably.”

Ahead of Ukrainian President Volodymyr Zelenskyy’s visit to the White House on Monday, President Donald Trump had a direct message to the Ukrainian leader on social media, stating he could end the war "almost immediately."

"President Zelenskyy of Ukraine can end the war with Russia almost immediately, if he wants to, or he can continue to fight," Trump wrote Sunday evening.

In an additional post, Trump referred to the upcoming meeting as a "Big Day," stating his excitement about the number of European leaders visiting.

"Big day at the White House tomorrow. I've never had so many European leaders at one time. It’s my great honor to host them!!!" Trump wrote.

Additionally, Trump reiterated his longstanding position that Ukraine should not join NATO, stating, "NO GOING INTO NATO BY UKRAINE. Some things never change!!!"

-ABC News' Kelsey Walsh

Former Vice President Mike Pence said he supports President Trump's decision to deploy the National Guard in Washington, D.C., to address crime. Pence had earlier advocated for an deployment of National Guard troops and federal resources to the Capitol during the Jan. 6, 2021, riots, an initial request that was ignored by Trump while Pence was in holding.

"Well, January 6 was a tragic day, but I know we did our duty that day. I wish the president would have done more, but I welcome his decision to deploy the National Guard and essentially federalize the D.C. police department," Pence said during an interview with CNN's “State of the Union.”

"I think it's important what the president is doing. I fully support it, and I think the American people welcome the president taking decisive action to ensure the streets of our nation's capital are safe and also continues to provide resources across the country to make all of our cities and towns and communities safe," he continued.

-ABC News’ Kelsey Walsh

National Guard troops deployed to Washington, D.C., remain unarmed as of Sunday, but Defense officials said that could change if the Guard is given different orders, particularly as their footprint is expected to grow.

Whether troops are armed will depend upon their mission, the officials said.

The number of troops in D.C. is expected to grow to 1,176 in coming days. There are currently 826 personnel mobilized in the nation’s capital with another 350 Guard troops coming from West Virginia.

-ABC News’ Anne Flaherty