Al-Dhafra Air Base, September 1: Jared Kushner and U.S. officials visited a major American air base in the United Arab Emirates on Tuesday, speaking to Emirati pilots on the tarmac, near the advanced F-35 fighter jets that the UAE hopes to buy as it normalizes relations with Israel.

The visit to Al-Dhafra Air Base by President Donald Trump's son-in-law came just before the El Al flight that had brought the U.S.-Israeli delegation to Abu Dhabi was to depart. It also happened as Iran's supreme leader called the United Arab Emirates' recognition of Israel “treason that will not last for long," an apparent threat underlining the risks inherit in the rapprochement. First Ever Isreal-UAE Direct Commercial Flight Lands in Abu Dhabi: Benjamin Netanyahu Speaks to Pilot, Says ‘It Is a Historic Day’.

The US delegation arrived in the UAE on an El Al plane on Monday in the first-ever direct commercial passenger flight between the two countries. The flight followed an agreement brokered by the Trump administration last month that saw the two countries establish diplomatic relations.

While at the base near Abu Dhabi, Kushner and U.S. National Security Adviser Robert O'Brien met Emirati Maj. Gen. Falah al-Qahtani, a top defense official. “Our relationship has been built on trust and mutual support,” al-Qahtani told reporters. “We have stood together to fight extremism in all of its forms.” O'Brien added that the U.S. expected a “significant security aspect” in the Israel-UAE normalization, without elaborating. Journalists also toured a joint command center run by both the U.S. and the UAE at the site.

Kushner, not wearing a facemask amid the coronavirus pandemic, shook hands with the U.S. and Emirati pilots gathered for the event. He also left a written message at the base. “May the relationship with America continue to grow and together, through strength, will benefit as we bring more peace and prosperity to the Middle East and beyond!” he wrote.

But as the visit drew to a close, state media in Iran begin broadcasting Ayatollah Ali Khamenei's remarks, which referred the UAE's recognition of Israel as a “stain” on the country.

“The United Arab Emirates committed treachery against either the Islamic world or Arab nations and regional countries, as well as Palestine," Khamenei said. “The treason will not last for long.” Both the UAE and Israel share a mutual suspicion of Iran. The UAE's day-to-day ruler, Sheikh Mohammed bin Zayed Al Nahyan, long has warned about Iran's intentions, particularly its nuclear program. That's a concern shared by Israeli Prime Minister Benjamin Netanyahu.

Iran long has insisted its program is only for peaceful purposes. But since Trump unilaterally withdrew from the 2015 Iran nuclear deal, Tehran has broken all the limits the accord placed on its program amid a series of escalating incidents in the region. An Emirati official dismissed Khamenei's comments.

“The path to peace and prosperity is not through incitement and hate speech,” Foreign Ministry official Jamal al-Musharakh said. “That kind of rhetoric is counterproductive to peace in the region.”

The journalists' visit to Al-Dhafra shows the change in the relationship between the Emirates and the U.S., which established defense deals with the UAE, a federation of seven sheikhdoms on the Arabian Peninsula, amid the 1991 Gulf War. Emirati special forces deployed to Afghanistan after the 2001 American-led invasion that followed the Sept. 11 attacks.

But the U.S. military for years only vaguely referred to Al-Dhafra as a base in “southwest Asia.” In recent years, the UAE has been far more willing to acknowledge the U.S. presence here and elsewhere in a country that hosts some 5,000 American troops. Dubai's Jebel Ali port also is the U.S. Navy's busiest port of call outside of America.

Al-Dhafra has hosted the F-35 for years, as well as surveillance aircraft, armed drones and refueling planes. The American delegation's visit to the base during the this tour suggests the F-35 sale remains a key part of the deal.

The UAE has touted the normalisation deal as a tool to force Israel into halting its contentious plan to annex parts of the West Bank sought by the Palestinians for their future state. It also may help the Emiratis acquire advanced U.S. weapons systems that have been previously unattainable, such as the F-35 fighter jet. Currently, Israel is the only country in the region with the stealth warplanes.

Netanyahu has publicly denied any connection between the normalization deal and the U.S. providing advanced weaponry to the UAE. The Palestinians, however, have fiercely opposed the normalization as peeling away one of their few advantages in moribund peace talks with Israel. Palestinians have held public protests and burned the UAE flag in anger.

Meanwhile Tuesday, Netanyahu issued a statement saying the two countries signed an agreement on banking and finance. "These understandings will help us advance mutual investments and broad cooperation," Netanyahu said in a statement.