Gulf allies of the United States, led by Saudi Arabia and the United Arab Emirates, are urging President Donald Trump to continue prosecuting the war against Iran, arguing that Tehran hasn't been weakened enough by the monthlong U.S.-led bombing campaign, according to U.S., Gulf and Israeli officials.

After private grumbling at the start of the war that they were not given adequate advance notice of the U.S.-Israeli attack and complaining the U.S. had ignored their warnings that the war would have devastating consequences for the entire region, some of the regional allies are making the case to the White House that the moment offers a historic opportunity to cripple Tehran's clerical rule once and for all.

Hundreds of protesters took to the streets across the embattled Palestinian territories Tuesday in outrage after Israel's parliament passed a measure establishing the death penalty by hanging for Palestinians convicted of murdering Israelis.

Palestinians young and old held sit-ins and marches in the Israeli-occupied West Bank, the territory where the new law is most sweeping. It orders West Bank military courts — which try only Palestinians — to make the death penalty the default sentence for those convicted, except in special circumstances.

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.

U.S. Secretary of State Marco Rubio on Monday voiced hope for working with elements within Iran's government, saying the United States privately had received positive messages, AFP reported.

Rubio said there were internal "fractures" inside Iran and that the United States hoped that figures with "power to deliver" take charge.

U.S. President Donald Trump said Monday that the United States is in "serious discussions" with "a new, and more reasonable, regime" in Iran with the aim of ending "military operations."

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.

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.

Israel's parliament on Monday passed its annual budget in a marathon overnight session, ensuring that Prime Minister Benjamin Netanyahu's government can complete its term until the fall.

Israel needed to pass a budget before April 1 in order to avoid triggering early elections. Netanyahu still reserves the right to call early elections before then if he wants.

U.S. President Donald Trump openly mused about seizing Iran's Kharg Island oil terminal in the Persian Gulf and the United States and Israel kept up their attacks Monday on the Islamic Republic, even as there were signs of progress in nascent ceasefire talks. Tehran, meanwhile, struck a key water and electrical plant in hard-hit Kuwait, part of its campaign targeting the Gulf Arab states.

As a diplomatic effort being facilitated by Pakistan toward ending the war moved ahead, Trump said Iran had agreed to allow 20 oil tankers through the Strait of Hormuz starting Monday as "a sign of respect." At the same time, with 2,500 U.S. Marines now in the region and a similar sized contingent on its way, he raised the idea of taking Iran's Kharg Island.

Syria's military said a large-scale drone attack targeted its bases near the border with Iraq on Monday, the latest such incident since the outbreak of the Middle East war.

In a statement, the army reported "a large-scale attack by a number of drones targeting several army bases near the Iraqi border at dawn today", adding that most of the drones were intercepted.