Israel carried out a new wave of strikes on Iran Monday, while Tehran warned that it would strike electricity plants across the Middle East and mine the Persian Gulf.
The war, now in its fourth week, has already seen several dramatic turning points – the killing of Iran’s supreme leader, the bombing of a key Iranian gas field and strikes targeting oil and gas facilities and other civilian infrastructure in Gulf Arab nations.
The conflict has killed more than 2,000 people, shaken the global economy, sent oil prices surging, and endangered some of the world’s busiest air corridors.
Iran’s promise of retaliation now threatens to raise the stakes yet again, with potentially catastrophic repercussions for civilians across the region.
Israel, meanwhile, launched new attacks Monday on the Iranian capital, saying it had "begun a wide-scale wave of strikes” on infrastructure targets in Tehran without immediately elaborating.
Explosions were heard in multiple locations in the afternoon. It wasn’t immediately clear what had been hit.
With the U.S. deploying more amphibious assault ships and additional Marines to the Middle East, Iran warned against any ground attack.
"Any attempt by the enemy to target Iran’s coasts or islands will, naturally and in accordance with established military practice, lead to the mining of all access routes ... in the Persian Gulf and along the coasts," Iran’s Defense Council warned said in a statement.
The widespread use of mines could imperil not only military vessels but scores of commercial ships waiting to pass through the Strait of Hormuz and a cleanup would last long after the conflict ends.
Trump has said he has no plans to send ground forces into Iran, but has also said that he retains all options. Israel has suggested its ground forces could take part in the war.
Israel has also targeted the Iran-linked armed group Hezbollah in Lebanon during the war, while the group has fired hundreds of rockets into Israel.
In recent days, Israel has hit many apartment buildings in Beirut and bombed bridges over the Litani river in southern Lebanon.
Lebanese President Joseph Aoun called the targeting of bridges "a prelude to a ground invasion," while Egypt denounced the strikes as the "collective punishment" of civilians for the actions of Hezbollah.
Authorities say Israeli strikes have killed more than 1,000 people in Lebanon and displaced more than 1 million.
Iran’s death toll has surpassed 1,500, its Health Ministry has said. In Israel, 15 people have been killed by Iranian strikes.
At least 13 U.S. military members have been killed, along with more than a dozen civilians, in the occupied West Bank and Gulf Arab states.