Gulf hostilities flared again on Wednesday, with an Iranian missile attack damaging Kuwait's airport and the US military carrying out strikes near the Strait of Hormuz, as diplomacy between Washington and Tehran showed little progress.

The latest flare-up, which sent oil prices up more than 1%, comes with the conflict stalemated in a shaky ceasefire and the Strait of Hormuz largely closed, more than three months after initial US and Israeli strikes on Iran.

Flights at Kuwait International Airport were suspended and diverted elsewhere until further notice, the state news agency said, citing aviation authorities, after an Iranian drone and missile attack on its T1 building.

The attack caused injuries and severely damaged some airport facilities, it added, but gave no further details. Kuwait Airways suspended operations after the attack, the airline said in a statement.

Bahrain's army intercepted three missiles and several drones, it said in a statement.

Earlier, the US Central Command said two Iranian missiles shot at Kuwait fell short or broke up in flight, while several ballistic missiles aimed at regional targets failed and three missiles heading for Bahrain were intercepted.

Since the conflict began, Iran has repeatedly attacked targets in the Gulf region home to US military bases.

Central Command said the US military also downed Iranian drones targeting civilian ships in regional waters and US forces in Kuwait, and carried out strikes on Qeshm Island near the Strait of Hormuz following attempted attacks by Iran.

Iran's state media said the elite Islamic Revolutionary Guard Corps (IRGC) attacked the headquarters of the US Fifth Fleet in Bahrain, as well as an airbase and helicopters in an unspecified regional country.

It sent missiles and drones in response to what the IRGC described as a US attack on a communications tower south of Qeshm.

Central Command said all the attacks failed, however, and US forces stayed ready to repel "unwarranted Iranian aggression."

Last week, Iran and the United States said they had reached a tentative initial agreement to halt the war, but they have yet to sign off on the deal.

Iranian media said Tehran has not communicated with Washington for several days, but US President Donald Trump said negotiations had not stopped.

"The conversations between us have been going on continuously, including four days ago, three days ago, two days ago, one day ago, and today," he said in a social media post.

DISCUSSIONS ON NUCLEAR PROGRAMME

Since mid-March, Trump has repeatedly said he is close to a deal to end the fighting and allow negotiators to tackle thorny issues, including the future of Iran's nuclear programme.

Trump has said his top priority is to stop Iran from acquiring nuclear weapons. Iran denies it is developing a nuclear bomb and says its atomic programme is for peaceful purposes.

Tehran is seeking access to billions of dollars in oil revenues, waivers on crude exports, a lifting of a US blockade on its ports and continued leverage over the strait, traversed by a fifth of the world's oil and liquefied natural gas traffic before the war.

Iranian media said the IRGC's navy targeted a vessel it identified as the Panaya with missiles in response to what it said was a US attack on an Iranian tanker near Hormuz.

"Disrupting the security of the Strait of Hormuz will carry a heavy price for the US military," media cited the IRGC as saying.

US Secretary of State Marco Rubio told lawmakers on Tuesday that the US would agree to sanctions relief only if Iran agreed to give up its nuclear activity.

"The war is over," Rubio declared during a sharp exchange with Democratic Senator Cory Booker of New Jersey, who disagreed.

ISRAEL KEEPS UP STRIKES IN LEBANON

The war has killed thousands since it began on February 28, mainly in Iran and Lebanon, while also causing global economic pain ⁠by pushing up energy prices.

It also triggered the latest round of conflict between Israel and Lebanese militant group Hezbollah, with Israel pursuing its deepest incursion into Lebanon in 25 years.

On Tuesday, Israel kept up strikes on a string of southern towns, Lebanese security sources said, despite a US-mediated partial ceasefire unveiled on Monday.

The move failed to reassure many Lebanese, 1.2-million of whom have been displaced, and an Israeli drone over Beirut kept residents on edge on Tuesday.

"Every time we return to our homes, there is a warning for us to be displaced again," said Faten Al Chehime, who fled to a displacement camp on Monday from her home in Beirut's southern suburbs, just two weeks after she had returned.

On Tuesday, the world's largest shipping group, MSC, said two projectiles struck one of its vessels while in Iraq's Umm Qasr port the previous day.

The IRGC said it carried out the attack in retaliation for a US attack on an Iranian vessel in the Gulf of Oman.

Children's agency UNICEF flagged the widening humanitarian crisis as surging transport prices and supply chain disruptions hinder life-saving aid to countries from Gaza to Nigeria.