The director of the FBI, Christopher Wray, told Congress Tuesday that the danger to American targets around the world has ramped up considerably since Israel began its war against Hamas and is now at levels not seen since ISIS attempted to build its caliphate in Iraq and Syria several years ago.

In testimony before the Senate’s Homeland Security Committee, Mr. Wray said intelligence officials have not identified any specific threats on American soil but they are concerned about so-called “lone wolf” extremists inspired by Hamas’ violent rhetoric.

“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 told the committee. “In just the past few weeks, multiple foreign terrorist organizations have called for attacks against Americans and the West.”

The threat of terrorism has been elevated throughout the year, he added, “but the ongoing war in the Middle East has raised the threat of an attack against Americans in the United States to a whole other level.”

He said the FBI does not have evidence that Hamas has the “intent or capability” to strike targets on American soil, but that the agency cannot discount the possibility.

“Here in the United States, our most immediate concern is that violent extremists — individuals or small groups — will draw inspiration from the events in the Middle East to carry out attacks against Americans going about their daily lives,” he warned in written remarks prepared for the committee.

Hamas is not the only threat to American interests, he said. Iran and its proxies in the Middle East, most notably the Hezbollah terrorists in Lebanon, as well as more established groups such as al Qaeda and ISIS, have issued calls to action in recent weeks.

“We’re keeping a close eye on what impact recent events may have on those groups’ intentions here in the United States, and how those intentions might evolve,” Mr. Wray said.