Iran's Revolutionary Guards seized an Israeli-linked cargo ship in the Strait of Hormuz on Saturday, the Iranian state-run IRNA news agency reported, days after Tehran warned it could close the area to sea traffic.
IRNA reported that a Guards helicopter had boarded and taken into Iranian waters the Portuguese flagged MSC Aries.
Shipping security agencies had earlier reported a vessel being boarded and seized by "regional authorities" in the Hormuz Strait between the United Arab Emirates and Iran.
The Aries is leased by international shipping line MSC from Gortal Shipping, an affiliate of Zodiac Maritime, Zodiac said in a statement, adding that MSC is responsible for all vessel activities. Zodiac is partly owned by Israeli businessman Eyal Ofer.
The incident comes amid rising regional tensions since the start of Israel's campaign in Gaza in October, with Israel and its ally the United States clashing repeatedly with Iranian-aligned groups in Lebanon, Syria, Iraq and Yemen.
Iran has threatened to retaliate for suspected Israeli airstrikes on its consulate in Syria's capital Damascus on April 1 that killed seven Revolutionary Guards officers including two senior commanders.
US President Joe Biden said on Friday he expected Iran to attack Israel "sooner, rather than later" and warned Tehran not to proceed.
Israel's military spokesperson, Rear Admiral Daniel Hagari, said: "Iran will bear consequences for choosing to escalate this situation any further", in response to reports of the seizure of MSC Aries.
On Tuesday the naval head of the Revolutionary Guards, Alireza Tangsiri, said it could close the Strait of Hormuz if deemed necessary.
He said Iran viewed as a threat Israel's presence in the UAE, with which Israel established diplomatic relations in 2020 as part of the "Abraham Accords" mediated by the United States.
Yemen's Iran-backed Houthi group has disrupted global trade with attacks on shipping in the Red Sea for months, saying it is aiming at vessels linked to Israel in retaliation for Israel's campaign in Gaza.