(NEXSTAR) – Sen. Patrick Leahy of Vermont, the most senior U.S. senator who is presiding over the impending Trump impeachment trial, has been taken to the hospital.

In a statement sent to multiple media outlets, spokesman David Carle said Leahy started “not feeling well” in his Capitol office.

“He was examined in the Capitol by the Attending Physician,” Carle said. “Out of an abundance of caution, the Attending Physician recommended that he be taken to a local hospital for observation, where he is now, and where he is being evaluated.”

No further information was available.

Leahy, 80, serves as president pro tempore of the Senate, meaning he presides over the Senate in the vice president’s staid. He is also third in line for the presidency.

As the pro tem, Leahy and U.S. Rep. Nancy Pelosi, the speaker of the House, have to sign all legislation passed by the Congress before any bill can be sent to the president’s desk for signing.

Leahy also served as Senate president pro tem from December 2012 to January 2015, his office said.

Hours before the hospital visit, Leahy commenced his role of presiding over the Senate impeachment trial of former President Donald Trump by swearing in his fellow lawmakers. The actual trial will begin next month.

This is a developing story.

The Associated Press contributed to this report.