US President Donald Trump has formally launched his re-election campaign, urging supporters to "keep this team in place" for four more years.
The Republican president made his case before thousands of supporters at a rally in Florida, calling the state "my second home".
Mr Trump used the announcement to lash out at Democrats, accusing them of trying to "rip your country apart".
Early polls place Mr Trump behind some potential Democratic challengers.
"We are going to keep America great again," the president said at an Orlando rally on Tuesday night. "Tonight I stand before you to officially launch my campaign for a second term as president of the United States."
"Together we stared down a broken political establishment and we restored government by and for the people," he recalled of his first campaign, declaring it "a great political movement".
"As long as you keep this team in place, we have a tremendous way to go. Our future has never looked brighter or sharper."
Mr Trump returned to his 2016 campaign pledge of cracking down on illegal immigration, warning that his Democratic challengers wanted to legalise migrants crossing the southern border.
A day earlier, the president tweeted that authorities would start "removing the millions of illegal aliens who have illicitly found their way into the United States".
What did Trump say about deportations?
Mr Trump tweeted on Monday night that undocumented migrants in the US would be "removed as fast as they come in".
US Immigrations and Customs Enforcement (ICE) typically does not announce raids, and the agency's officials told US media they had been unaware the president would tweet about the plans.
Earlier this month, acting ICE Director Mark Morgan said authorities would target migrants who have received final orders of deportation, including families.
In his Monday night tweets, Mr Trump also contrasted Mexico's "strong immigration laws" - the product of a new agreement to avert US tariffs - with US Democratic border policies.
As a part of the deal, Mexico is deploying 6,000 National Guard personnel to its borders to crack down on Central American migration.
A senior Mexican official told the Associated Press news agency the number of migrants arriving at the US border had already dropped from 4,200 to 2,600 per day.