Iran backs Hamas against Israel and it accuses the United States of backing what it calls Israeli crimes in Gaza, where weeks of bombardment have killed thousands of people and driven most of the population from their homes.
"They shall soon await the closure of the Mediterranean Sea, (the Strait of) Gibraltar and other waterways," Tasnim quoted Brigadier General Mohammad Reza Naqdi, coordinating commander of the Guards, as saying.
Yemen's Iran-aligned Houthi group has over the past month attacked merchant vessels sailing through the Red Sea in retaliation for Israel's assault on Gaza, leading some shipping companies to switch routes
The White House on Friday said Iran was "deeply involved" in planning operations against commercial vessels in the Red Sea.
Iran has no direct access to the Mediterranean itself and it was not clear how the Guards could attempt to close it off, although Naqdi talked of "the birth of new powers of resistance and the closure of other waterways".
"Yesterday, the Persian Gulf and the Strait of Hormuz became a nightmare for them, and today they are trapped ... in the Red Sea," Naqdi was quoted as saying.
The only groups backed by Iran on the Mediterranean are Lebanon's Hezbollah and allied militia in Syria, at the far end of the sea from Gibraltar.
Iran's Defence Minister Mohammad Reza Ashtiani warned that a proposed US-backed multinational task force to protect shipping in the Red Sea would face "extraordinary problems", official Iranian media reported on Thursday.
Ashtiani's comments came after the United States said last week it was in talks with other countries to set up a task force following a spate of attacks by the Iran-backed Houthis in Yemen on ships in the Red Sea.
"If they make such an irrational move, they will be faced with extraordinary problems," Ashtiani told the official Iranian Student News Agency (ISNA) in its comments
"Nobody can make a move in a region where we have predominance," he said, referring to the Red Sea.
Ashtiani did not specify what measures Iran was prepared to take in response to the setting up of a US-backed Red Sea task force.
US National Security Advisor Jake Sullivan told reporters last week that Washington was in talks with "other countries" over forming a "maritime task force ... to ensure safe passage of ships in the Red Sea," but did not give further details.
Yemen's Houthis, which are aligned with Iran, have waded into the Israel-Hamas conflict by attacking vessels in vital shipping lanes and firing drones and missiles at Israel more than 1,000 miles from their seat of power in the Yemeni capital of Sanaa.
American and French navies have strengthened their presence in the Red Sea to protect vessels from the risk of seizure or attack by the Houthis.
