Donald Trump “has to” announce a campaign for the Republican presidential nomination in 2024 in the next two weeks, according to a senior source close to Trump, if the former president wants to head off being indicted under the Espionage Act after the FBI search at Mar-a-Lago last week.

In communications reviewed by the Guardian, the source indicated Trump needed to announce because politically it would be harder for the US Department of Justice (DoJ) to indict a candidate for office than a former president out of the electoral running.

A source also suggested Ron DeSantis, Trump’s only serious competitor in Republican polling, will not run in 2024 if Trump chooses to enter the race.

“He can wait,” the source said of the Florida governor.

In contrast, a former White House official said Trump could yet decide not to run, for fear of losing his grip on his party and role as a kingmaker should an indictment force him to drop out of the race.

A search warrant unsealed on Friday showed that the FBI seized from Mar-a-Lago five sets of top secret documents, three sets of secret documents and three sets of confidential documents, as well as other records.

It was reported that some seized documents concerned nuclear weapons. Trump called that report a “hoax”.

The warrant also revealed Trump to be under investigation for possible violations of the Espionage Act, which dates from 1917 and has been used to go after whistleblowers.

If charged and convicted, Trump could face up to 20 years in federal prison or be barred from running for office.

Trump denies wrongdoing, claiming he had the authority to declassify documents and that the FBI seized documents protected by attorney-client and executive privilege.

But his legal jeopardy extends further.

The House January 6 committee and the DoJ continue to investigate Trump’s attempts to overturn the 2020 election and incitement of the deadly US Capitol attack.

Trump is also under investigation in New York, over his business and tax affairs, and in Georgia, regarding attempts to overturn his defeat by Joe Biden.

On Monday it was confirmed that Rudy Giuliani, the former mayor of New York who became Trump’s personal attorney, is the target of a criminal investigation in Georgia, over his role in the attempt to overturn the election.

Also on Monday, a judge ruled that Lindsey Graham, a Trump ally and Republican senator from South Carolina, could not avoid testifying in the Georgia investigation.

Having long teased a new White House run, Trump seized on the FBI search at Mar-a-Lago for fundraising purposes, portraying it as an unprecedented raid and claiming mistreatment by political opponents. Senior Republicans echoed his claims, seemingly demonstrating Trump’s continuing hold on the party.

Last week, a Trump attorney, Alina Habba, said she thought Trump could end his legal troubles by announcing that he would not run for the presidency again.

Habba told Real America’s Voice: “I’ve sat across from him, every time he gets frustrated, I say to him: ‘Mr President, if you would like me to resolve all your litigation, you should announce that you are not running for office, and all of this will stop.’ That’s what they want.”

But Habba also said: “I hope he runs. I told him, ‘This is going to actually increase your support in your base because they just always take it a little too far.’ The Democratic party, they can’t get out of their own way sometimes.”