The United States is on high alert and preparing for an "inevitable" attack after Iran vowed retaliation for a suspected Israeli strike on its consular office in Syria that killed seven members of its Islamic Revolutionary Guard Corps, including two generals, according to reports.

"We're definitely at a high state of vigilance," a U.S. official told Reuters about an attack that could come as soon as next week.

Senior U.S. officials told CNN that an attack is "inevitable," saying Iran could target American or Israeli assets in the region.

At a funeral for the seven in Tehran where marchers changed "death to Israel" and burned U.S. flags, Gen. Hossein Salami, the commander of the IRGC, said Israel "cannot escape the consequences" of its alleged actions in Syria and for the war in Gaza against Hamas.

"The Zionist regime cannot escape the consequences of the harm it does," he said. "It is exposed and knows very well what is going to happen."

President Joe Biden discussed the threat with Prime Minister Benjamin Netanyahu during their Thursday phone call. 

"Our teams have been in regular and continuous contact since then. The United States fully supports the defense of Israel against threats from Iran," a senior Biden administration official told Reuters.

The attack, attributed to Israel, on the Iranian compound in Damascus has stoked already heightened tensions in the region because of the six-month war in Gaza between Israel and Hamas, and threatens to widen the conflict in the region. 

Hamas operates as one of Iran's proxies in the Middle East, along with Hezbollah in Lebanon and the Houthis in Yemen.