Maine shooting: New details emerge in Robert Card's death

President Joe Biden said in a statement Thursday, "Once again, our nation is in mourning after yet another senseless and tragic mass shooting."

He said he's "praying for the Americans who’ve lost their lives, for those still in critical care, and for the families, survivors, and community members enduring shock and grief."

"Far too many Americans have now had a family member killed or injured as a result of gun violence. That is not normal, and we cannot accept it," Biden said.

He said, while the nation has made progress on gun reform with "the Bipartisan Safer Communities Act, the two dozen executive actions I’ve taken, and the establishment of the first-ever White House Office of Gun Violence Prevention, it’s simply not enough."

Biden said he's urging Republicans in Congress to "work with us to pass a bill banning assault weapons and high-capacity magazines, to enact universal background checks, to require safe storage of guns, and end immunity from liability for gun manufacturers."

"This is the very least we owe every American who will now bear the scars -- physical and mental -- of this latest attack," he said.

"Last night, Lewiston became yet another community torn apart by senseless gun violence," Vice President Kamala Harris added on Thursday.

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VP Harris hints at effectiveness of gun control at luncheon with Australian PM

"It does not have to be this way, as our friends in Australia have demonstrated," Vice President Harris said at a state luncheon honoring Australian PM Anthony Albanese.

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Harris, speaking at a State Department luncheon as part of the Australian prime minister's visit to Washington, D.C., noted how Australia enacted transformative gun reform after a 1996 mass shooting, banning semi-automatic and other weapons. Gun-related deaths in Australia then dropped significantly.

"The leading cause of death of American children is gun violence," Harris said. "Gun violence has terrorized and traumatized so many of our communities in this country. And let us be clear, it does not have to be this way, as our friends in Australia have demonstrated."

Biden received another briefing on the shooting Thursday morning and has ordered the U.S. flag to be flown at half-staff at the White House and all public buildings and grounds, according to the White House.

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White House has message for Speaker Johnson: 'Now's the time to find common ground'

White House press secretary Karine Jean-Pierre called on House Speaker Mike Johnson and Congress to act on gun reform.

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-ABC News' Ben Gittleson

Bates College, a liberal arts school in Lewiston, Maine, remains on lockdown with students ordered to shelter in place as the manhunt for the mass shooter intensifies.

"One college employee was present at one of the shooting locations and was injured, but is expected to make a full recovery," college President Garry Jenkins said. "Two students were also near one of the crime scenes but were unharmed."

"Our thoughts are with those who have close ties to those who were killed or injured," he said. "Unfortunately, as the search for the person of interest continues, we remain in an emergency situation under shelter-in-place orders."

The first shots were fired at Just-In-Time Recreation, a bowling alley in Lewiston, Maine, formerly known as Sparetime.

"None of this seems real, but unfortunately it is," the owners of the bowling alley said in a statement. "We are devastated for our community and our staff. We lost some amazing and wholehearted people from our bowling family and community last night. There are no words to fix this or make it better. We are praying for everyone who has been affected by this horrific tragedy. We love you all and hold you close in our hearts."

Minutes after the massacre at the bowling alley, the mass shooting continued at the nearby Schemengees Bar & Grille Restaurant.

"My heart is crushed. I am at a loss for words. In a split second your world gets turn upside down for no good reason," a statement from Schemengees said. "We [lost] great people in this community. How can we make any sense of this. Sending out prayers to everyone."

Three people are in critical condition and five others are in stable condition on Thursday morning in the wake of Wednesday night's mass shooting, according to Dr. John Alexander, chief medical officer at Central Maine Health Care.

Two patients have been transported to other hospitals and two others have been discharged, he said.

Alexander praised the work of the hospital staffers who jumped in to help. He said about 100 off-duty team members volunteered.

-ABC News' Alex Faul