State TV said Iran seeks to end the war on all fronts, including in Lebanon, and ensure the security of shipping. Washington’s latest proposal had addressed a deal to end the war, reopen the Strait of Hormuz and roll back Iran’s nuclear program, an issue that Tehran would rather discuss later.

There was no immediate comment from the White House about Iran’s reply.

President Donald Trump is giving diplomacy “every chance we possibly can before going back to hostilities,” the U.S. ambassador to the United Nations, Mike Waltz, told ABC.

Meanwhile, the fragile ceasefire was tested Sunday when a drone ignited a small fire on a ship off Qatar, while the United Arab Emirates and Kuwait reported drones entering their airspace. The UAE blamed Iran for its attack. No casualties were reported, and no one immediately claimed responsibility.

The Qatari Foreign Ministry called it a “dangerous and unacceptable escalation that threatens the security and safety of maritime trade routes and vital supplies in the region.”

Iran and armed allied groups have used drones to carry out hundreds of strikes since the war began with U.S. and Israeli attacks on Feb. 28.

Iran says it’s on ‘full readiness’ to protect nuclear sites

Trump has reiterated threats to resume full-scale bombing if Iran does not accept an agreement to reopen the strait and roll back its nuclear program. Iran has mostly blocked the strategic waterway key to the global flow of oil since the war began, rattling world markets.

The U.S. in turn has imposed a blockade of Iranian ports. On Friday, the U.S. struck two Iranian oil tankers that it said were trying to breach the blockade. Iran’s Revolutionary Guard navy has reiterated its warning that any attack on Iranian oil tankers or commercial vessels would be met with a “heavy assault” on one of the U.S. bases in the region and enemy ships.

Another sticking point in negotiations is the fate of Iran’s highly enriched uranium. The U.N. nuclear agency says Iran has more than 440 kilograms (970 pounds) of uranium that is enriched up to 60% purity, a short, technical step from weapons-grade levels.

In an interview with state media posted late Saturday, a spokesman for Iran’s military said its forces were on “full readiness” to protect nuclear sites where uranium is stored.

“We considered it possible that they might intend to steal it through infiltration operations or heliborne operations,” Brig. Gen. Akrami Nia told the IRNA news agency.

The majority of Iran’s highly enriched uranium is likely at its Isfahan nuclear complex, International Atomic Energy Agency Director-General Rafael Mariano Grossi told The Associated Press last month. The facility was bombarded by U.S.-Israeli airstrikes in the 12-day war last year and faced less intense attacks this year.

Pakistan, which oversaw face-to-face talks between the U.S. and Iran last month, continues to pursue mediation. In rare public comments, Pakistani army chief Field Marshal Asim Munir said Islamabad remains committed to helping end the conflict. And Pakistani Prime Minister Shehbaz Sharif spoke by phone with Qatari counterpart Sheikh Mohammed bin Abdulrahman Al Thani.

Drone attacks target Gulf Arab nations

The UAE’s Defense Ministry said it shot down two drones and blamed the attack on Iran.

In Kuwait, Defense Ministry spokesman Brig. Gen. Saud Abdulaziz Al Otaibi said hostile drones entered Kuwait’s airspace early Sunday and forces responded “in accordance with established procedures.” The ministry did not say where the drones came from.

The Qatari Defense Ministry said a drone targeted a commercial ship coming from Abu Dhabi into a southern port, setting a small fire that was extinguished. The United Kingdom Maritime Trade Operations Center said the attack happened 23 nautical miles (43 kilometers) northeast of Qatar’s capital, Doha. It provided no details about the ship’s owner or origin, and there was no claim of responsibility.

There have been several attacks against ships in the Persian Gulf over the past week.

South Korea announced initial findings from a investigation that said two unidentified airborne objects struck the stern of the South Korean-operated vessel HMM NAMU about one minute apart while it was anchored in the Strait of Hormuz last week, causing an explosion and fire. A foreign ministry spokesperson said officials have yet to determine who was responsible.