Commandos from Iran's paramilitary Revolutionary Guard rappelled from helicopters Saturday in a dramatic raid and seizure of a British container ship near the Strait of Hormuz.

The action was launched as Israel and its allies are preparing for an expected attack on Israel by Iran.

Iran's state-run IRNA said a special forces unit of the Iranian Guard's navy carried out the attack. The ship was identified as the MSC Aries, a Portuguese-flagged container that's associated with London-based Zodiac Maritime, the Associated Press reported. Zodiac Maritime is part of Israeli billionaire Eyal Ofer's Zodiac Group. 

The brazen raid comes amid increasingly fraught tensions as Israel and its Western allies gear up for an expected Iranian attack on Israel. Iran has vowed retaliation for an attack on Syria nearly two weeks ago days ago that killed 13 people. Israel has not claimed responsibility for the assault on Syria. 

Sources said Friday that an attack on Israel could occur by Saturday. A U.S. Defense Department official said that additional assets were being moved to the Mideast to "bolster regional deterrence efforts and increase protection for U.S. forces." 

It was unclear whether the seizure of the ship may have been the expected military action.

President Biden noted earlier this week that Iran was threateninga "significant attack," and he vowed to offer "ironclad" support to Israel. 

On Friday he warned Iran simply: "Don't."