Republican congressman Steve Scalise is "in some trouble" after being shot at a baseball field but "he's going to be okay, we hope", Donald Trump said.
The US president offered the assessment as a shaken US House returned into session a day after the shooting of Mr Scalise and others.
"It's been much more difficult than people even thought at the time," Mr Trump said of the treatment of Mr Scalise, the No 3 GOP leader, who is in critical condition and underwent a third surgery at the MedStar Washington Hospital Centre.
Mr Trump visited the Louisiana congressman at the hospital on Wednesday night, and Vice President Mike Pence paid a visit on Thursday morning.
"Steve in his own way may have brought some unity to our long-divided country," Mr Trump added.
"We've had a very, very divided country for many years. And I have a feeling that Steve has made a great sacrifice, but there could be some unity being brought to our country. Let's hope so."
As the House returned to business, lawmakers sought some semblance of normalcy even as they offered prayers for the wounded and echoed the president in pledges of unity.
Two Capitol Police officers sustained relatively minor injuries, as did a congressional aide, and they have been released from hospitals.
However, a congressional aide-turned-lobbyist, Matt Mika, was shot multiple times and critically injured, and he remained in hospital.
"When tragedy strikes we are family," said Representative Nanette Barragan, who plays on the Democratic baseball team and invited all to attend the congressional charity baseball game at Nationals Park on Thursday night.
Mr Scalise and the others had been at the GOP team's baseball practice in nearby Alexandria, Virginia, when they were shot. He was fielding balls at second base when he was hit in the hip, and sustained grievous injuries as the bullet travelled through his pelvis and injured internal organs.
In the immediate aftermath on Wednesday the extent of his injuries was not widely known.
The shooter was identified as James T Hodgkinson, a 66-year-old home inspector from Illinois who had several minor run-ins with the law in recent years and belonged to a Facebook group called "Terminate the Republican Party".
Over social media he had lashed out at Mr Trump and the GOP. Capitol Police officers in Mr Scalise's security detail returned fire, and Hodgkinson later died from his wounds.
Earlier on Thursday, Republican lawmakers met behind closed doors to share reflections and pray. They signed oversized cards for the wounded. Yet politics was never far off.
Some Republican lawmakers blamed the shooting on vitriolic political rhetoric, particularly rising from the left in the era of Mr Trump.
I am sickened by this despicable act. Let me be as clear as I can be. Violence of any kind is unacceptable in our society. pic.twitter.com/ib2reH3ghQ— Bernie Sanders (@SenSanders) June 14, 2017
Speaking on the House floor, Representative Glenn Thompson issued a call to "replace the hateful rhetoric and resistance with respect".
Representative Steve King said over Twitter: "The centre of America is disappearing, and the violence is incited by the leading cultural voices of the Left."
House Democratic leader Nancy Pelosi lashed out angrily at such comments.
"How dare they say such a thing? How dare they?" she exclaimed.
She noted that she has received numerous threats herself over the years, and is currently the target of millions of dollars in negative ads in a House district in Georgia where a hard-fought special election will take place next week.
Ms Pelosi noted that Mr Trump resorted to violent language at times on the campaign trail, and she accused Republicans of "sanctimony" in seeking to place blame on the left.