Fighting in the Middle East intensified on multiple fronts on Tuesday, with the region waking up to the possibility of an oil spill following an attack on a fully loaded Kuwaiti oil tanker in Dubai waters.

The tanker, Al Salmi, which was docked at the port in the United Arab Emirates, caught fire after being attacked by Iranian forces at about 12:10 am, the Kuwait Petroleum Corporation said. Emergency services and firefighters were dispatched to help bring the situation under control.

Rising uncertainty following the incident shook energy markets, with the average price of a gallon of gas in the United States reaching over $4 for the first time in almost four years.

Bahrain, Saudi Arabia and Qatar also reported intercepting strikes overnight.

In Iran, a wave of military strikes rattled the country in the past 24 hours, with the ISNA news agency reporting an attack on the city of Mahallat in Markazi Province on Monday, allegedly killing 11 people and injuring 15.

The Iranian Red Crescent Society said its aid workers launched rescue operations in the capital, Tehran, and the northwestern city of Zanjan.

In Israel, eight people were reported injured amid Iran's missile attack on central Israel, The Times of Israel reported on Tuesday. Strikes were also reported in Bnei Brak, Ramat Gan, and Petah Tikva, with footage showing cars on fire.

US Secretary of State Marco Rubio warned Iran of consequences over the closure of the Strait of Hormuz during an interview with Al Jazeera.

He said indirect communication between Tehran and Washington is ongoing through intermediaries and that President Donald Trump "always prefers diplomacy".

In an interview with US broadcaster Newsmax, Israeli Prime Minister Benjamin Netanyahu gave no timeline for ending the war, but claimed the mission is at the halfway point.

In Lebanon and beyond, anger erupted following the deaths of three Indonesian peacekeepers on Monday.

The soldiers were part of the Indonesian contingent deployed under the United Nations Interim Force in Lebanon. France called on the UN for an emergency meeting on Tuesday.

'Heinous attacks'

The Indonesian Ministry of Foreign Affairs condemned the incident. "The recurrence of such heinous attacks against Indonesian peacekeepers within a short span of time is utterly unacceptable," it said.

This cannot be treated as an isolated occurrence, but reflects a rapidly deteriorating security environment in southern Lebanon, where continuing Israeli military operations have placed UN peacekeepers at grave risk, it added.

The ministry mourned the loss of the fallen peacekeepers and said Indonesia stands in solidarity with their families, while wishing a swift recovery to those injured.

"Indonesia calls for an immediate, thorough and transparent investigation to establish the facts, including the circumstances and those responsible, and stresses that full accountability must follow," it said.

Dina Yulianti Sulaeman, director of the Indonesia Center for Middle East Studies, called the killing of Indonesian peacekeepers "dangerous" and said it changes the situation.

It "demonstrates how the current escalation in the Middle East is no longer limited to direct confrontations between states, but now affects international peacekeeping missions and neutral actors", Sulaeman said.

The incident has affected public opinion in Indonesia, which is growing increasingly hostile toward the US and Israel, she said.

The Indonesian government had previously joined the US-led "Board of Peace", expressing its willingness to join the International Stabilization Force. However, this was "completely disregarded by the US and Israel", she said, adding that Israel has "completely ignored Indonesia's position".

"This tragic incident shows that the US and Israeli aggression on Iran has triggered a chain reaction throughout the region, impacting everyone," she said.

Sulaeman warned that "serious and just diplomatic intervention" was needed, namely, stopping the attacks by the aggressor rather than asking Iran, the victim of the aggression, to stop its resistance and efforts to protect its sovereignty.

Without that, "the conflict could continue to escalate geographically and politically", she added.

In another development, Spain has closed its airspace to US planes involved in attacks on Iran, Defense Minister Margarita Robles said on Monday.

"We will not authorize the use of Moron and Rota (military bases) for any acts related to the war in Iran," she said, adding that Spain had made this clear to the US government from the beginning.

Italy also denied permission for US military aircraft to land at the Sigonella air base in Sicily before heading to the Middle East in operation against Iran, Reuters reported on Tuesday, citing the country's Corriere della Sera newspaper.