New York Rep. Jerrold Nadler received medical attention Friday after he appeared to faint during a news conference with Mayor Bill de Blasio in Manhattan.

The 71-year-old lawmaker has been in the spotlight and under enormous pressure in recent months. He is a leader of efforts by House Democrats to investigate President Donald Trump for corruption and whether he obstructed Special Counsel Robert Mueller's Russia investigation.

"It's impossible to sit next to this man without thanking him … for all he's doing for this nation," de Blasio said during the news conference.

Nadler was seated next to the mayor in the gym at P.S. 199 on the Upper West Side for an announcement about the city's speed camera program when he slumped over in his chair. He was briefly disoriented while doctors at the event tended to him. Nadler was given water and an orange to eat. Staff cleared reporters from the school gymnasium where the event was taking place. Paramedics were called and the congressman was taken to Lenox Hill Hospital.

"Congressman Nadler is doing much better. I spent time with him and the medical personnel and the EMTs who responded. He got more energetic with every passing minute. We gave him water and juice and he's doing much, much better," de Blasio said at a news conference after the health scare. "He's an extraordinary public servant. This entire country is depending on him right now."

Nadler's spokesman said the congressman never lost consciousness. A short time after he arrived at the hospital, Nadler let people know he was doing better:

Trump and Nadler first butted heads more than 30 years ago, when Trump proposed building a housing complex on Manhattan's West Side while Nadler was the local Assemblyman. Trump often mentions their tangled history, most recently this week.

"And now, Jerry Nadler, who I've fought for a long period of my life because he's from Manhattan," Trump said at an unrelated news conference. "I know him well. I've had great success against Jerry, and I will again."

Nadler's committee has also subpoenaed the Department of Justice for the full Mueller Report. Nadler also said this week that he expected he expects Mueller to testify before the committee, although it might be behind closed doors.