WASHINGTON – The Secret Service was investigating a report yesterday that a hand grenade was thrown at the stage during President Bush’s speech in the former Soviet republic of Georgia.

After Mr. Bush left Georgia yesterday, the Secret Service was informed by Georgian authorities of a report that a device, possibly a hand grenade, had been thrown within 100 feet of the stage during Mr. Bush’s speech, hit someone in the crowd, and fell to the ground, a Secret Service spokesman, Jonathan Cherry, said.

According to the report, a Georgian security officer picked up the device and removed it from the area. The Secret Service had not seen the device as of yesterday evening, Mr. Cherry said. It has agents in Tbilisi working with the FBI, State Department, and Georgian authorities to investigate the report.

A Georgian Interior Ministry spokesman, Guram Donadze, at first said no grenade was thrown close to Mr. Bush, calling it a lie, but later said the secretary of Georgia’s National Security Council, Gela Bezhuashvili, would make an announcement about the reports today.

Officials from the National Security Council and President Saakashvili’s office could not be reached for comment.

The White House referred questions to the Secret Service.

Mr. Cherry said he couldn’t characterize the source of the report that a device had been thrown.

Mr. Bush was returning to America late yesterday after a four-country trip that also included stops in Russia, Latvia, and the Netherlands. He was the first American president to visit Georgia.