President Donald Trump speaks about the arrest in the mail bomb scare at the 2018 Young Black Leadership Summit in the East Room of the White House, Friday, Oct. 26, 2018, in Washington. Credit: Andrew Harnik | AP

WASHINGTON – President Donald Trump lamented Friday that the news media was more focused on covering “ this ‘Bomb’ stuff” rather than politics, a development he asserted was slowing Republican momentum in advance of the Nov. 6 midterms.

“Republicans are doing so well in early voting, and at the polls, and now this ‘Bomb’ stuff happens and the momentum greatly slows – news not talking politics,” Trump said in a midmorning tweet. “Very unfortunate, what is going on. Republicans, go out and vote!”

His tweet came about an hour before federal authorities announced an arrest in Florida of a man suspected of sending the potentially explosive devices to public figures, the latest of whom included Sen. Cory Booker, D-N.J., and former director of national intelligence James Clapper Jr.

Packages sent to Booker and Clapper – recovered in Florida and New York – pushed the total number of devices found by law enforcement to 12. None have detonated, but all have pushed officials onto high alert as they worry about additional devices being delivered.

[Florida man charged after weeklong bomb-package scare]

At the outset of a White House event early Friday afternoon, Trump took a different tone than in his tweet, praising law enforcement officers for their swift work and calling for national unity.

“The bottom line is that Americans must unify, and we must show the world that we are united together in peace and love and harmony as fellow American citizens,” Trump said. “There is no country like our country, and every day we are showing the world just how truly great we are.”

The president also promised the prosecution of anyone responsible for sending the explosive devices “to the fullest extent of the law.”

“These terrorizing acts are despicable and have no place in our country,” he said at the outset of a previously scheduled event for young conservative African American leaders.

But a more partisan Trump soon reemerged at the event in the East Room, where many attendees wore “Make America Great Again” hats, called out Trump’s name and chanted “USA” and “Build the wall,” the latter a reference to the president’s long-promised wall at the U.S.-Mexico border.

During his remarks, Trump, who recently declared himself a “nationalist,” derided “globalists,” saying: “I like the globe too, but we have to take care of our people.”

As he referenced globalists, some in the crowd called out “Soros” – a reference to prolific Democrat donor George Soros – and then chanted “lock him up!”

“Lock him up,” Trump repeated from the lectern, laughing.

[Bomb threats highlight risk of violent political rhetoric]

Soros was among those sent suspicious packages by the suspected serial bomber.

The group later cheered as Trump recounted his efforts to appeal to black voters during the 2016 campaign, including his pitch, “What the hell do you have to lose?”

Trump’s was quickly rebuked for his tweet by the top Senate Democrat.

“Pathetic,” Senate Minority Leader Charles Schumer, D-N.Y., wrote on Twitter. “When potential terrorism strikes, we should be pulling together, not playing politics.”

Until his appearance at the White House early Friday afternoon, Trump had otherwise remained silent about the latest developments in an episode that has unsettled the nation.

Earlier, in a tweet posted shortly after 3 a.m., the president criticized CNN, another recipient this week of a suspicious package, saying the network had been “blaming me” for the work of a suspected serial bomber.

The individual recipients of the packages have all been outspoken critics of the president.

[Secret Service intercepts ‘potential explosive devices’ sent to Obama, Clinton]

In separate tweets Friday morning, Trump wrote about illegal immigration and questioned whether Twitter was motivated by political bias in removing followers from his account.

He returned the subject of the bomb investigation later, thanking law enforcement authorities involved.

“I want to applaud the FBI, Secret Service, Department of Justice, the U.S. Attorneys’ Office for the Southern District of New York, the NYPD, and all Law Enforcement partners across the Country for their incredible work, skill and determination!” Trump said.

The Washington Post’s Seung Min Kim and Ben Strauss contributed to this report contributed to this report.