Fresh U.S. strikes triggered air defenses in Tehran on Wednesday after President Donald Trump warned he was "not finished" with a war with Iran that has already cost his nation $37.5 billion.

After the foes' fighting over the strategic Strait of Hormuz led to the collapse of a preliminary deal, the Middle East war has expanded to include the region's other key chokepoint for global oil supplies.

U.S. President Donald Trump announced Tuesday that he has directed his administration to "allow all U.S. airline carriers to fly directly to Lebanon so that Americans can easily visit this beautiful land."

President Joseph Aoun on Tuesday expressed gratitude for the United States' support of Lebanon following his meeting in Washington with counterpart Donald Trump at the White House.

President Joseph Aoun met Tuesday at the White House with his U.S. counterpart Donald Trump, who said that the Lebanese leader is “highly respected.”

Lebanon's military said Tuesday that Israeli troops fired near its soldiers deploying in a so-called "pilot zone" Israel is to withdraw from under a U.S.-backed agreement.

While troops were deploying in Zawtar al-Gharbiyeh in southern Lebanon, Israeli forces "opened fire in the vicinity of these units", the army said, adding that "the attack will hinder the implementation of deployment in the pilot zones".

Kuwait said Tuesday that Iran had again attacked power and desalination plants critical to the tiny desert nation.

The statement from Kuwait’s Electricity, Water and Renewable Energy Ministry said that Tehran had struck the plants for a fourth day in a row on Monday night.

On the road to south Lebanon's coastal town of Naqoura, an Israeli flag hung over the deep blue sea, a stone's throw away from a metallic grid marking the Israeli-announced "security zone".

"Turn around, you don't have permission to pass," an Israeli soldier said through a loudspeaker to a convoy of journalists, including AFP, who joined a Christian NGO on an organized tour of still-inhabited villages in the occupied area.

President Joseph Aoun is set to meet with his U.S. counterpart Donald Trump in Washington on Tuesday, as pressure builds for Beirut to disarm Hezbollah, Israel's key condition before withdrawing from south Lebanon.

It comes a day after the United States, which has sponsored negotiations between Lebanon and Israel, announced the start of the implementation of an agreement granting the Lebanese army control over "pilot zones" in southern Lebanon.

The Lebanese army deployed on Tuesday to "pilot zones" in part of the country that had been under Israeli control following a deal sponsored by Washington, a military source told AFP.

The source said soldiers "have begun deploying to the village of Zawtar al-Gharbieh" in the Nabatieh region, following Israel's invasion of parts of the south during their war with Hezbollah.

Yemen's Iran-backed Houthi rebels on Monday announced a maritime embargo of their foe Saudi Arabia, after the pair traded fire last week for the first time in years.

The rebels "declare a maritime embargo against the criminal Saudi enemy, based on the equation of 'an eye for an eye,' effective immediately upon the issuance of this statement," military spokesman Yahya Saree said.