The United Arab Emirates has inked a $2.8 billion deal with American companies to purchase military transport aircraft. The deal indicates a bolstering of defense ties between the Gulf and the United States in the shadow of the Iranian threat. Agreements were signed with US giants Boeing Co. and Lockheed Martin Corp. and were announced at the ninth International Defense Conference and Exhibition in Abu Dhabi. The deals include the purchase of four C-17 aircraft from Boeing and 12 C-130J Super Hercules aircraft from Lockheed Martin. Despite an economic downturn, the UAE has invested almost $4 billion in defense deals over the past few days. But Francis Tusa, editor of Defense Analysis newsletter, noted that Abu Dhabi was holding vast oil revenues and has plenty of money to spend on defense. "We're not talking about the UAE, but specifically about Abu Dhabi," he said. "They're sitting on top of a sovereign wealth fund of several hundred billion dollars, so they've got money." "If you are any of the Gulf states, you'll always make sure you buy significant batches of American equipment, not least the perception that if something nasty happens you'll be able to turn to the US for help. That's been a staple of Gulf defense security policy for 35-40 years," he told The Media Line. Earlier this week the UAE signed an agreement with US manufacturer Raytheon for the delivery of the company's anti-aircraft missiles that can be launched both on the ground and in the air. The UAE's air force will become the first in the region to acquire the latest and most advanced versions of Raytheon's medium-range air-to-air missile as part of the country's modernization plan, aimed at establishing a multilayer missile-defense system. The UAE, similar to other Gulf countries, is an ally of the US and is eyeing Iran's nuclear ambitions with concern. Iran refuses to capitulate to international pressure to abandon its controversial nuclear program. The international community is concerned Tehran is secretly manufacturing a nuclear bomb, although Iran insists the program is for the peaceful purpose of creating energy. The predominantly Sunni Gulf countries are unhappy about the prospect of a nuclear Shi'ite Iran in the neighborhood. Besides the strategic concerns, any military showdown between western forces and Iran could have a major impact on the Gulf's economy, as Iran controls strategic waterways that are crucial for oil exports. In addition, the UAE has a long-standing territorial dispute with Iran over three small islands located in the Strait of Hurmuz, which the UAE claims Iran is occupying illegally.