The F.B.I. says the Israel-Hamas war raises the potential for an attack against Americans in the U.S.

Christopher A. Wray, the F.B.I. director, warned U.S. senators on Tuesday that the violence between Israel and Hamas has raised the potential for an attack against Americans in the United States to “a whole other level.”

“We assess that the actions of Hamas and its allies will serve as an inspiration the likes of which we haven’t seen since ISIS launched its so-called caliphate several years ago,” Mr. Wray said.

Several foreign terrorist organizations have called for attacks against Americans since Oct. 7, when Hamas gunmen carried out a gruesome attack against Israel that killed 1,400 people, Mr. Wray said. Islamic State, also known as ISIS, called for attacks on Jewish communities in the United States and Europe; the Lebanese militant group, Hezbollah, threatened to attack American interests in the Middle East; and Al Qaeda also issued a specific call to attack the United States, Mr. Wray said.

The most immediate concern, Mr. Wray said, was that individuals or small groups in the United States are inspired by the Oct. 7 attacks “to carry out attacks against Americans going about their daily lives.”

“That includes not just homegrown violent extremists inspired by a foreign terrorist organization, but also domestic violent extremists targeting Jewish or Muslim communities,” he said.

Mr. Wray pointed to an arrest in Houston on Oct. 19 of a Palestinian asylum seeker who had been in the United States since June 2019 on a travel visa that expired a few months later. Mr. Wray said that the man, who prosecutors identified as Sohaib Abuayyash, 20, had been studying how to build bombs and posted details online about his support for killing Jewish people.

Prosecutors said he was illegally in possession of a firearm and had been in contact with “others who share a radical mindset, has been conducting physical training and has trained with weapons to possibly commit an attack,” according to the criminal complaint, which was mostly redacted.

Mr. Wray’s testimony came as threats to Jewish, Muslim and Arab communities in the United States have been on the rise since the war began on Oct. 7.

Between Oct. 7 and Oct. 23, there were 312 antisemitic acts in the United States, according to the Anti-Defamation League. Those include a report on Oct. 15 at Grand Central Terminal in New York when someone punched a Jewish woman in the face because she was Jewish.

Over the same time period, the Council on American Islamic Relations, a civil rights organization, said it received more than 700 complaints, including reported bias incidents, since Oct. 7.

Glenn Thrush contributed reporting.