American commandos on the ground in Israel are helping locate the more than 200 hostages seized during Hamas’s surprise cross-border attacks on Oct. 7, the Pentagon’s top special operations policy official said on Tuesday.

“We’re actively helping the Israelis to do a number of things,” Christopher P. Maier, an assistant secretary of defense, told a special operations conference in Washington. He said that a main task was to help Israel “identify hostages, including American hostages. It’s really our responsibility to do so.”

Mr. Maier declined to say how many U.S. Special Operations forces were currently in Israel. But other U.S. officials say the Defense Department has dispatched several dozen commandos in recent weeks, in addition to a small team that was in Israel on Oct. 7 conducting previously scheduled training.

The officials, who spoke on condition of anonymity to discuss operational matters, said the commandos would join F.B.I., State Department and other U.S. government hostage-recovery specialists in their discussions with Israeli counterparts.

The U.S. Special Operations forces are not assigned any combatant roles in Israel, but they are talking through with their Israeli counterparts “what is going to be a very complex fight going forward” in Gaza, Mr. Maier said.

In his discussions with his Israeli counterpart, Defense Secretary Lloyd J. Austin II has stressed the need for careful consideration of how Israeli forces conduct a ground invasion of Gaza, where Hamas maintains an intricate network of tunnels under densely populated areas.

“We will work with them as much as possible to help advise them on those types of activities,” Mr. Maier said.

Several Western countries have secretly moved small teams of their own special forces closer to Israel to help with any potential rescue operation and to be nearby to assist in any large-scale evacuations of their citizens from Israel or Lebanon.

Mr. Maier said U.S. Special Operations forces in the region are also poised “to help our own citizens get out of places and to help our embassies be secure.”