Even as the United States strives to achieve detente with Iran, the United Arab Emirates, a key U.S. ally in the Persian Gulf, is seeking to buy 30 Lockheed Martin F-16 Block 61 combat jets and upgrade its 79 Block 60 aircraft.

The U.S. Defense Security Cooperation Agency has informed the U.S. Congress, which must approve the proposed sale, that it endorses the deal.

Given the close U.S. military links with the Emirates, which hosts U.S. forces at its giant al Dhafra air base, and the growing stress on export sales for U.S. defense companies, analysts believe the sale will go through.

The prospect of a new F-16 buy first surfaced last April, when U.S. Defense Secretary Chuck Hagel said Lockheed Martin would provide 25 Block 60 jets for $5 billion.

That was after the Emirates had apparently abandoned thorny negotiations with France's Dassault Aviation for the purchase of Rafale multirole fighters to replace the 43 aging Dassault Mirage 2000 fighters the Emirates bought two decades ago.

"Having sought information from Eurofighter for the Typhoon and Boeing for the F/A-18E/F Super Hornet, the Emirates dismissed the Typhoon on cost grounds in December," British defense analyst Gareth Jenkins observed.

"The Emirates have not clarified whether the Super Hornet is still being considered, or, with the additional F-16s now requested, if the requirement has now been put on hold entirely," he wrote in IHS Jane's Defense Weekly.

Matthew Hedges of the Institute for Near East and Gulf Military Analysis in Dubai suggests this could be a stopgap acquisition until Lockheed Martin's stealthy F-35 Joint Strike Fighter is available to the United States' Gulf allies.

"The upgraded avionics and communications systems, specifically to enable the upgraded UAE air force and air defense, will allow the UAE to not only efficiently communicate with next generation fighters such as the F-356 and the F-22 Raptor, but also streamline operational effectiveness when part of an international coalition, something they've had problems with," he said.

"This suggests," he told the U.S. weekly Defense News, "that the UAE will stick with an enlarged F-16 fleet until the F-35 becomes available for export as other options put forward to the UAE have failed to meet their operational requirements."

The Emirates are not likely to be able to acquire the JSF, the most advanced fifth-generation fighter and still under development, until after Israel has taken delivery of the 20 F-35s it has on ordered.

The United States has guaranteed that it will maintain Israel's technological supremacy in the Middle East.

The value of the Block 61 deal is likely to be in excess of the figure cited for the proposed Block 60 deal. The upgrade for the older Block 60s is valued at about $270 million.

The new aircraft and the upgrading of the Block 60 jets, along with the array of missiles the Emirates is seeking, will provide a major boost to the firepower of the gulf federation's air force, already arguably the strongest among the Arab monarchies in the region facing Iran.

Lockheed Martin declines to provide any details about the new model F-16 and how it differs from the Block 60s provided the Emirates air force.

The DSCA, the Pentagon unit that handles arms sales with U.S. allies, has not identified weapons and other systems ordered by the Emirates that pertain to the F-16 Block 61.

However, last October the Emirates requested the United States provide munitions and associated equipment, spare parts, training and logistical support under a possible $4 billion contract.

These included 5,000 of Boeing's precision-guided GBU-39B small diameter bombs with BRU-61 carriage systems, eight SDB guided test vehicles for aircraft integration, 300 Boeing AGM-84H standoff land attack missiles-expanded response, or SLAM-ERs, and 30 AWW-13 data link pods.

In 2009, the Emirates ordered 224 Raytheon AIM-120C-7 units, at the time the latest derivative of the advanced medium-range air-to-air missile, or AMRAAM, for the Block 60 F-16s. These should have been delivered by now.

IHS Janes observed that the Pentagon declined to say whether the Emirates' Block 60 aircraft would be upgraded to Block 61 standards, but the designation of Block-60+ for those aircraft would suggest that's not the case.