Biden orders independent probe of Trump rally's security after the assassination attempt on the former president

President Joe Biden on Sunday said that he has ordered an independent investigation into the security for the rally where a shooter attempted to assassinate former President Donald Trump .

"I've directed an independent review of the national security of yesterday's rally, and we will share the results of that independent review as well," he said on Sunday afternoon.

Biden reiterated his gratitude for the Secret Service agents and other law enforcement officers "who risked their lives, literally, for our nation."

There will also be a review of the security plan for the Republican National Convention, which begins in Milwaukee on Monday. Both the Trump campaign and the Republican National Committee have said that the party's major event will still go on as planned.

Biden said he had a "short but good conversation" with Trump.

"I'm sincerely grateful that he is doing well and is recovering," Biden told reporters. "Jill and I are keeping him and his family in our prayers."

The president also extended his condolences to Corey Comperatore , who was killed while shielding his family after shots rang out at the Trump rally. Biden did not identify Comperatore by name but said that "he was a father; he was protecting his family from the bullets that were being fired."

Biden pledged that he would address the question of national unity, a topic that has been brought up in the wake of the heinous attack, during an address to the nation later Sunday evening.

Keeping with the moment's weight, the president will speak from the Oval Office.

"Unity is the most elusive goal of all," Biden said, pledging "we are not going to lose sight of who we are as Americans."