By Phil Stewart

WASHINGTON, March 31 (Reuters) - Defense Secretary Pete Hegseth declined on Tuesday to reaffirm the U.S. commitment to NATO's collective defense, saying that would be up to President Donald Trump after key European allies refused to stand with the United States in the war against Iran.

The remarks by Hegseth at a Pentagon briefing were extraordinary, given that collective defense lies at the heart of the NATO alliance, which was formed in 1949 with the primary aim of countering the risk of Soviet attack on allied territory.

Iran's chokehold on the Strait of Hormuz has thrown the global economic system into turmoil, yet Israel, which launched attacks on Tehran alongside the United States, has emerged as a rare exception.

Since Israel and its US ally started the Middle East war on February 28, economies from Asia to Europe and the United States have come under pressure from surging oil and natural gas prices that have driven up fuel and electricity costs.

BEIRUT, March 31 (Reuters) - Three U.N. peacekeepers were killed this week in southern Lebanon, making the latest war between Israel and Hezbollah one of the deadliest chapters for a peacekeeping mission whose decades-long mandate expires this year.

The U.N. Interim Force in Lebanon (UNIFIL) first deployed in 1978 and has remained through successive conflicts, including a 2024 war during which its positions came under fire repeatedly.

March 31 (Reuters) - Initial findings of a probe into the deaths of two Indonesian peacekeepers in southern Lebanon point to a roadside explosion striking their convoy, the United Nations peacekeeping chief said on Tuesday.

The two peacekeepers with the UNIFIL force were killed on Monday near Bani Hayyan in south Lebanon and two other soldiers were wounded in the blast. Another Indonesian soldier was killed overnight Sunday into Monday when a projectile exploded near one of the group's positions.

(Corrects typographical error in headline)

March 31 (Reuters) - Iran's Supreme Leader Mojtaba Khamenei is in the country but is refraining from making public appearances "for understandable reasons", the RTVI news outlet quoted Russia's ambassador to the country as saying on Tuesday.

Mojtaba replaced his father, Ayatollah Ali Khamenei, who was killed when Israel and the United States launched their war on Iran more than a month ago. The U.S. has said it believes Mojtaba himself is wounded and likely disfigured.

BERLIN, March 31 (Reuters) - German Chancellor Friedrich Merz clarified on Tuesday comments he made about the return of Syrian refugees to their homeland after economists and politicians warned that a mass departure could have a serious economic effect.

At a press conference with Syrian President Ahmed al-Sharaa on Monday, Merz said some 80% of Syrians in Germany were expected to return to their home land in the next three years.

Fear for her son's fate kept Maisoun Shawamreh awake through the night in the occupied West Bank following the Israeli parliament's approval of a law permitting the execution of Palestinians convicted of deadly terror attacks.

"The mothers of prisoners -- none of us slept last night," Shawamreh told AFP as she joined a protest in Ramallah against the law on Tuesday.

Her son has been in detention for three years, awaiting sentencing on charges of attempted murder.

"He may or may not be subject to execution," she said, uncertain of what lies ahead.

By Maya Gebeily and Emilie Madi

BEIRUT, March 31 (Reuters) - Lebanon is preparing for the possibility that hundreds of thousands displaced by Israeli strikes and evacuation orders will not return home in the long term, Lebanese social affairs minister Haneen Sayed said on Tuesday.

Sayed spoke to Reuters after Israel's defence minister Israel Katz said the military would destroy all homes along Lebanon's border with Israel and bar 600,000 residents who fledsouthern Lebanon from returning to their villages.

By John Irish and Angelo Amante

PARIS/ROME, March 31 (Reuters) - France and Italy have joined Spain in pushing back on U.S.-Israeli military operations, sources said on Tuesday, as U.S. President Donald Trump singled out NATO allies in Europe as unhelpful in the month-long war, highlighting divisions.

The decisions came against a backdrop of tensions between Washington and key partners over the war in Iran. Earlier this month, Trump called longtime NATO ‌allies "cowards" over their lack of support against Iran.

By Anthony Deutsch

THE HAGUE, March 31 (Reuters) - The widening Iran conflict has led to airstrikes on infrastructure across the Middle East and threats to target oil facilities, electricity production sites and desalination plants that supply civilians, which some experts say could amount to war crimes if carried out.

WHAT DOES INTERNATIONAL LAW SAY?