U.S. forces struck targets across southern and western Iran Tuesday after President Donald Trump vowed retaliation for the deaths of American troops, while Tehran hit U.S. bases in the Gulf and a tanker was struck in the Strait of Hormuz.

Yemen's Iran-aligned Houthis announced a naval blockade on Saudi Arabia Monday, opening a potential new front in the war and raising the threat to global energy supplies and trade beyond the Gulf.

Shipping companies loading or discharging cargo at Saudi ports could be targeted "in any location" by Houthis, according to an email ​sent to companies Monday, Reuters reported.

Oil prices gained nearly 2% on the escalating cycle of attacks that ​has ⁠all but wrecked an interim peace agreement signed last month. But signs that Tehran and Washington want to resume diplomacy helped to limit price rises.

U.S. Central Command said it had hit Iranian military command centers, maritime capabilities, missile and drone launch sites and air defense systems in its latest round of strikes.

Explosions were heard around the city of Shiraz in southern Iran, state media said. Konarak and Chabahar on the southern coast, the city of Khorramabad and a civilian site outside the city of Abdanan, both in the west, all came under attack, media reports said.

Later, the IRNA news agency quoted an official in Khorramabad as saying no enemy attack had taken place there.

At least 50 civilians have been killed and 500 wounded in the recent U.S. strikes on Iran, a Health Ministry official said.

As hostilities spread across the region, the U.S. State Department issued a new "worldwide caution" for Americans due to "heightened tensions in the Middle East."

Iran strikes region

Iran launched renewed attacks across the Gulf, where recent strikes on desalination facilities have raised concerns about water shortages.

Attacks on Kuwaiti power generation and water desalination plants Monday caused several generation units to be taken out of service as a precautionary measure and ⁠repairs were ⁠underway, authorities said.

Iran's Revolutionary Guards said they targeted infrastructure in Bahrain belonging to U.S. tech company Amazon in response to what they described as a U.S. strike on the construction site of Iran's planned Darkhovin nuclear power plant.

Iranian state media reported that Iranian forces also targeted accommodation facilities of U.S. military personnel at Bahrain's Sheikh Isa Air Base.

There was no immediate comment from the U.S. military, Bahrain or Amazon on the reported incidents, which Reuters was unable to verify.

The Iranian army said it launched drone attacks against three U.S. military bases in Kuwait Tuesday. The Guards said they attacked a U.S. military site in Jordan, while Jordan said its forces intercepted and destroyed five Iranian drones.

Tankers struck

The maritime security agency UKMTO said Tuesday a tanker in the Strait of Hormuz reported being struck by a projectile, forcing its crew to abandon the vessel and board a lifeboat.

Also on Tuesday, Iran's Revolutionary Guards said two oil tankers had caught fire after explosions while attempting to transit the southern ⁠route of the strait.

Just four commodity vessels crossed the strait on Monday, mostly using the northern shipping lane near Iran's coast, down from seven the previous day, Kpler data showed.

Iran had been pressing the Houthis to close the Bab el-Mandeb gateway to the Red Sea if the U.S. continued to attack Iranian power infrastructure – putting two of the world's most vital energy arteries at risk.

A full closure of Bab ​el-Mandeb could reduce global oil supply by 7% as it would leave most Saudi oil exports unable to leave the region, adding to the 10% cut in oil flows ​from the war in the Gulf.

Diplomatic push

A senior Iranian official told Reuters on Monday that Tehran had received a proposal from mediators for a 10-day cease-fire in efforts to salvage the interim deal, intended to pave the way to a lasting agreement to end the war that began on Feb. 28 with U.S.-Israeli attacks on ‌Iran.

Israel has not ‌joined the latest round of strikes on Iran. "We have no desire to insert ourselves into this, but we ⁠are prepared for any scenario," Israeli Finance Minister Bezalel Smotrich said Tuesday.

Iranian Interior Minister Eskandar Momeni had asked ‌Pakistan to resume its mediation role in the conflict. He later arrived in Islamabad for further talks.

The latest phase of fighting has proved to be among the deadliest of the conflict for U.S. forces. U.S. troop deaths rose ​to 17 over the weekend.

Trump, under mounting pressure at ⁠home over rising gasoline prices since the war began, said the latest U.S. strikes on Iran were avenging the deaths of ⁠American service members.

"Every time Iran kills an American Soldier they will pay for that killing many times over!" he wrote on Truth Social on Monday.

The war has killed thousands ⁠of people, mostly in Iran and Lebanon. ​Parts of Lebanon remain under Israeli occupation following attacks on Israel by Hezbollah fighters, who said they were acting in solidarity with Tehran.

Lebanese President Joseph Aoun is due to meet Trump at the White House on Tuesday to present a plan on how to disarm Iran-aligned Hezbollah and secure an Israeli withdrawal.