Oil steadied and Asian stocks were mostly lower Tuesday as signs of a de-escalation of the Iran war remained mixed.

Tokyo's Nikkei 225 was down 1.6% to 51,063.72. Losses after the Iran war began on Feb. 28 have been wiping out the gains it made from the beginning of the year.

The United States hit the central Iranian city of Isfahan early Tuesday, sending a massive fireball into the sky, and Tehran struck a fully loaded Kuwaiti oil tanker in the Persian Gulf.

The attacks were testament to the intensity of the monthlong war the U.S. and Israel launched against Iran, which has maintained its chokehold on the Strait of Hormuz, closing off the vital waterway for global energy shipments, sending oil prices skyrocketing and roiling world markets.

Hundreds of thousands of Lebanese displaced by the escalating war between Israel and Hezbollah have poured into Beirut, seeking refuge wherever space is available.

Families from southern Lebanon and the southern suburbs of the capital known as Dahieh, where Hezbollah has its main operations and support base, are now living in makeshift tents along the Beirut corniche, in classrooms turned into shelters, a sports stadium and even inside hospitals.

Jean-Pierre Lacroix, the United Nations’ peacekeeping chief, told reporters Monday that it looks like Israel is expanding a buffer zone in southern Lebanon.

He said that given Israeli military statements and actions, "it certainly looks like we might end up with, I would call it, an expanded buffer zone in southern Lebanon."

Jeanine Hennis-Plasschaer, the U.N. special coordinator for Lebanon, issued a scathing statement Monday, saying that the humanitarian impact in southern Lebanon as Israel trades fire with Hezbollah has reached devastating levels.

The envoy detailed the three U.N. peacekeepers and nine Lebanese paramedics killed in just the last few days as a snapshot of the death toll that now stands at more than 1,240.

An armed man who crashed his pickup truck into a major Detroit-area synagogue earlier in March was inspired by Hezbollah and had sought to inflict as much damage as he could on Jewish people, the FBI said Monday.

Ayman Ghazali made a video just minutes before the attack at Temple Israel in West Bloomfield Township, saying he wanted to "kill as many of them as I possibly can" in the large Jewish congregation, said Jennifer Runyan, head of the FBI in Detroit, who announced the new information.

President Donald Trump on Sunday night said he has "no problem" with a Russian oil tanker off the coast of Cuba delivering relief to the island, which has been brought to its knees by a U.S. oil blockade.

"We have a tanker out there. We don't mind having somebody get a boatload because they need … they have to survive," Trump told reporters as he flew back to Washington.

Spain has closed its airspace to U.S. planes involved in the Iran war, Defense Minister Margarita Robles said Monday, marking another step in the country's opposition to the U.S. and Israel's conflict in the Middle East.

Spain had already said the U.S. could not use jointly operated military bases in the Iran conflict, which Spanish Prime Minister Pedro Sánchez has described as illegal, reckless and unjust.

Iran on Monday defied Lebanon's expulsion order for its ambassador by saying he would stay, further increasing tensions in a country in the crosshairs of the latest fighting between the Iranian-backed Hezbollah and Israel.

Lebanon had declared Ambassador Mohammad Reza Shibani "persona non grata" in an effort to weaken Iran's diplomatic presence and have a charge d'affairs at its embassy instead. But the deadline to leave the country was Sunday.

Sirens sounded at dawn near Israel's main nuclear research center, a part of the country that has been targeted repeatedly in recent days. Israel's military also said it had taken out two drones launched from Yemen, where the Iranian-backed Houthi rebels entered the war on Saturday with their first missile attack.

Later, a fire broke out at an oil refinery in the northern city of Haifa, one of only two in Israel, either from a missile strike or from debris falling from an interception. The blaze was quickly extinguished.