WASHINGTON - Sen. Thom Tillis, R-N.C., collapsed while running a race in Washington on Wednesday morning, but later said he was "doing well."

Tillis, a Republican elected in 2014, tweeted at about 7:45 a.m. Wednesday that he planned to run in the American Council of Life Insurance's Capital Challenge three-mile team race, a charity event attended by many members of Congress and the media.

At about 8:50 a.m., the Associated Press reported that Tillis first appeared unconscious, but was breathing when taken from the race. While near the finish line, he was taken away by a U.S. Park Police helicopter to a hospital.

About an hour later, Tillis posted a message on Twitter, saying "I'm fine."

"Just running about two-and-a-half miles in, got overheated," he said. "See you back on the Hill."

The race is held annually in Anacostia Park.

Members of Congress posted well-wishes on Twitter.

"Thinking about my good friend @SenThomTillis this morning and praying for a quick recovery," wrote Sen. Bob Corker, R-Tenn. Sen. Tim Kaine, D-Va., tweeted, "Please keep my colleague @SenThomTillis in your prayers. Wishing him a quick recovery."

Tillis is a member of the Senate Armed Services, Judiciary, Veterans Affairs and Banking, Housing and Urban Affairs committees, and the Senate Special Committee on Aging.