The Biden administration is expressing concerns about a potential Iranian attack following the assassination of Hezbollah leader Hassan Nasrallah by Israel, a U.S. official told CNN. 

Joint defenses are being coordinated with Israel to counter any retaliation, alongside adjustments in U.S. military posture, the official revealed. 

In response to growing fears of a regional conflict, the U.S. has stepped up its military preparedness. The Biden administration has previously led multinational efforts to defend Israel, notably in April when Iran launched over 300 drones and missiles at Israel. That attack came after Israeli airstrikes targeted senior Iranian Revolutionary Guard officers in Syria.

While the U.S. official declined to specify the nature of the anticipated attack or the specific military measures being taken, the Pentagon issued a warning to Iran and its allies.

“Should Iran, its partners, or its proxies use this moment to target American personnel or interests in the region, the United States will take every necessary measure to defend our people,” Defense Department spokesman Gen. Patrick Ryder said. He also highlighted the presence of significant U.S. military assets in the region, including the USS Abraham Lincoln Carrier Strike Group.

Despite the setbacks, the Biden administration remains focused on finding a diplomatic solution to prevent the conflict from spiraling further.

“There needs to be an effort to de-escalate here,” said John Kirby, the White House’s national security spokesman, in an interview with CNN on Sunday. “We believe and continue to believe that an all-out war with Hezbollah, certainly with Iran, is not the way to do that. If you want to get those folks back home safely and sustainably, we believe that a diplomatic path is the right path.”