President Donald Trump said the United States was starting direct, high-level talks with Iran over its nuclear program on Saturday, in a shock announcement during a White House meeting with Israeli Prime Minister Benjamin Netanyahu.

Speaking Monday in the Oval Office, Trump said he was hopeful of reaching a deal with Tehran, but warned that the Islamic republic would be in "great danger" if the talks failed.

Tehran confirmed discussions were set for Saturday in Oman, but stressed they were "indirect" talks.

Talks on Monday between Israeli Prime Minister Benjamin Netanyahu and US President Donald Trump are expected to be dominated by Washington's shock tariffs on Israel and escalating tensions with Iran.

Netanyahu becomes the first foreign leader to meet with Trump in the US capital since the president unveiled sweeping levies on multiple countries in his "Liberation Day" announcement on Wednesday.

Gaza's civil defence agency said Israeli strikes killed at least 44 people on Sunday as Israel's prime minister vowed a "strong response" to a rare salvo of rockets fired from the Hamas-ruled territory.

Dozens of Palestinians have been killed almost daily since Israel resumed its military offensive in Gaza on March 18, ending a two-month ceasefire that had brought relative calm to the territory.

Tens of thousands of people demonstrated in Morocco's capital on Sunday against the conflict in the Gaza Strip where Israel has resumed its anti-Hamas offensive after a two-month ceasefire.

The largest pro-Palestinian protest in the capital Rabat for several months was called by the Islamist-dominated coalition the Justice and Development party.

Protesters were accompanied by chanting and the beating of drums as they marched down the city's Mohammed V Avenue near parliament.

They waved flags including one bearing the image of slain Hamas chief Yahya Sinwar.

Israel staged a strike in south Lebanon on Sunday that it said had targeted Hezbollah, and authorities said killed two people, as a US envoy visited for talks on the militant group and economic reforms.

The strike came more than four months into a fragile truce between Israel and Hezbollah, and a day after US deputy special envoy for the Middle East, Morgan Ortagus, discussed disarming the Iran-backed with senior figures, according to a Lebanese official.

Batons in hand, Tunisian police marched in single file down a dirt path flanked by olive trees. Ahead of them, migrants fled as their tents burned.

Some migrants stood by helplessly, watching the smoke swirl into the sky just a few hundred metres (yards) away after the authorities torched what had been their temporary homes.

"I don't know what to do," said Bakayo Abdelkadeur, a 26-year-old from Mali, clutching two worn blankets.

Iran's top diplomat has dismissed direct negotiations with the United States as pointless, his office said Sunday, after US President Donald Trump said he preferred face-to-face talks over its nuclear programme.

Trump sent a letter to Iran's supreme leader Ayatollah Ali Khamenei last month calling for negotiations but warning of military action if diplomacy failed.

On Thursday, the US president said he favoured "direct talks", arguing they were "faster" and offered a better understanding than going through intermediaries.

Israeli Prime Minister Benjamin Netanyahu is set to travel to Washington to meet with US President Donald Trump, discussing issues including tariffs and the "Iranian threat," his office said Saturday.

The meeting will take place on Monday, a White House official said on condition of anonymity.

The two countries are dealing with a set of extremely thorny issues, including Trump's shock imposition of 17 percent tariffs on Israeli imports, an elusive search for a ceasefire in Gaza, and mounting concern over Iran's nuclear program.

Senior Lebanese officials said Saturday's talks with visiting US deputy special envoy for the Middle East Morgan Ortagus were positive, focusing on south Lebanon amid a fragile truce between Israel and Hezbollah.

President Joseph Aoun and Ortagus discussed "south Lebanon, the work of the international monitoring committee and the Israeli withdrawal" from Lebanese territory, a statement from the presidency said, characterising the talks as constructive.

A video recovered from the cellphone of an aid worker killed in Gaza alongside other rescuers shows their final moments, according to the Palestinian Red Crescent, with clearly marked ambulances and emergency lights flashing as heavy gunfire erupts.

The aid worker was among 15 humanitarian personnel killed on March 23 in an attack by Israeli forces, according to the United Nations and the Palestinian Red Crescent.