Attorney General Michael Mukasey is "conscious, conversant and alert" after collapsing during a speech in Washington Thursday evening, according to a Justice Department spokesman.
But there is still no word on exactly why Mukasey fell ill.
Mukasey, 67, had been delivering remarks on combating international terrorism to the Federalist Society's annual meeting at the Marriott Wardman Park Hotel.
A lawyer in the room said Mukasey "started struggling with [his] speech, slurring" just before he collapsed.
"His vital statistics are strong and he is in good spirits," Justice Department spokesman Peter Carr said in a statement released late Thursday evening just before midnight. "He is receiving excellent care and appreciates all of the good wishes and prayers he has received. The doctors will keep him overnight for further observations."
According to Justice Department staff, the attorney general collapsed around 10:20 p.m. ET. Medical personnel including "the attorney general's security detail and a doctor who was on the scene" administered emergency first aid after his collapse, Carr said.
As the security detail closed in around Mukasey, the crowd remained seated; some began to cry.
EMTs, whom dinner attendees told ABC News arrived 20 minutes after people in the crowd and Mukasey's security detail called 9-1-1, then transported him to George Washington University Medical Center.
A high-level source who was near Mukasey at the scene told ABC News he appeared "responsive" when he left the hotel on a stretcher.
Two people who were in the front of the hotel ballroom and had a good view of the unfolding situation agreed that Mukasey was alert. One saw him moving his hands and feet; the other saw him moving his mouth and talking.
As emergency personnel took Mukasey out of the room, one of the attendees heard them tell Mukasey they had his glasses.
. Mukasey's chief of staff and other high-level members of his team arrived at the hospital Thursday night.
Justice Department officials made no indication that Mukasey would turn his powers over to the deputy attorney general, Mark Filip, who joined other department staff at the hospital Thursday night.
Federal agents released the crowd from the hotel's ballroom at about 10:40 p.m. ET.
Multiple sources described Mukasey's collapse to ABC News, saying he was delivering a strong speech defending the Bush administration's legal policies on the War on Terror and taking direct aim at critics on the left and in the media.
At one point, a state court judge in the audience stood and yelled, "you tyrant." Mukasey continued his remarks in a grim, dispassionate tone, calmly refuting the criticism and expressing hope the next President will realize the tools he has been given.
But about 20 minutes into the speech, Mukasey began to make a coughing or gurgling sound, according to audience members. He tried to continue his remarks, but began slurring his words. He then very laboriously managed to get out one monosyllabic word and began teetering at the podium.
A man on the dias ran to catch the attorney general as he fell.
President Bush nominated Mukasey, a former federal judge, to his post in September 2007. He took the helm at the Justice Department last November.
Mukasey inherited a department racked by scandal after the much-criticized firings of at least nine U.S. attorneys in 2006 and allegations by Democrats that his predecessor, Alberto Gonzales, misled lawmakers during congressional hearings.