WHCA dinner shooting live updates: Suspect planned to target as many people as possible: Sources

Acting Attorney General Todd Blanche said Sunday that "the system worked" and kept President Donald Trump and other leaders safe from the shooting Saturday night at the White House Correspondents' Association Dinner that they were attending.

"The system worked; law enforcement and the Secret Service protected all of us. The man barely got past the perimeter. And so when you have a perimeter designed to keep people safe, like President Trump, and it works - that's something that should be applauded," Blanche told "This Week" anchor George Stephanopoulos.

Blanche said the suspect, whom law enforcement has identified as 31-year-old Cole Allen from Torrance, Calif., was likely acting alone, although investigations are ongoing.

"We believe that he traveled by train from Los Angeles to Chicago and then Chicago to Washington, D.C.," Blanche said.

Asked how the suspect may have gotten a firearm into the hotel, Blanche replied, "It's a good question. And listen, I'm not sure. It appears that he checked in on the 24th (of April) to the hotel, and we're still looking at video surveillance and footage of where he walked and how he got in and how those firearms got in, but at the end of the day, I expect we'll have a lot more about that in the coming days."

-ABC News' Oren Oppenheim

Cole Thomas Allen, the suspect in the White House Correspondents' Association dinner shooting, is being held the Washington, D.C., Metropolitan Police Department's Third District after being released form an area hospital overnight, according to law enforcement sources.

Allen is expected to appear in court on Monday.

A Secret Service Uniformed Division officer was also treated and released overnight from a different area hospital, according to sources.

-ABC News' Jack Date

Britain's King Charles and Queen Camilla reached out to President Donald Trump following the incident at the White House Correspondents' Association Dinner, according to a royal source.

"Their Majesties have reached out privately to The President and First Lady to express their sympathies with all those affected on the night and their gratitude to the security services who prevented further injury," a royal source told ABC News.

The king and queen are scheduled to arrive on Monday in Washington, where they'll be hosted by Trump and first lady Melania Trump for a state visit, according to the White House.

ABC News' Zoe Magee

International leaders expressed their shock and pledged their solidarity with the White House early on Sunday, after a suspect allegedly exchanged gunfire with authorities outside the White House Correspondents' Association Dinner.

"I am shocked by the scenes at the White House Correspondents' Dinner in Washington overnight," British Prime Minister Keir Starmer said in a statement. "Any attack on democratic institutions or on the freedom of the press must be condemned in the strongest possible terms."

He added that it was a "huge relief" that both Trump and first lady Melania Trump, along with the other attendees, were safe after the event.

The suspect's alleged actions were condemned by members of the governments of Kuwait, Pakistan, the United Arab Emirates and a host of other countries.

French President Emmanuel Macron decried the incident, saying, "The armed attack targeting the President of the United States last night is unacceptable. Violence has no place in a democracy. I extend my full support to Donald Trump."

"No political hatred can find space in our democracies," Italian Prime Minister Giorgia Meloni said. "We will not allow fanaticism to poison the places of free debate and information. The defense of the culture of confrontation must remain the insurmountable bulwark against every intolerant drift, to safeguard the values that found our Nations."

Israeli Prime Minister Benjamin Netanyahu said in a statement released by his office that he was "shocked" by the event, but glad the president and first lady "were safe and strong."

"We send our wishes for a full and speedy recovery to the wounded police officer and salute the US Secret Service for their swift and decisive action," Netanyahu said, according to his office.

Lebanon's president, Joseph Aoun, sent Trump a cable after the incident, according to his office.

"And President Aoun expressed in his cable full solidarity with President Trump in the face of such regrettable events that target security and stability, affirming his strong condemnation of acts of violence in all their forms, and wishing that the United States of America enjoys security and safety," Aoun's office said.