The United Arab Emirates expects to finalize a $7 billion contract to buy Lockheed Martin's high-altitude missile defense system in the next few months, officials of the U.S. defense giant say.

The deal would mark the first time that the Terminal High Altitude Area Defense system has been sold to a foreign state and underlines Washington's efforts to establish a Persian Gulf-wide shield against Iranian ballistic missiles among U.S. allies in the region.

These states, including oil-rich Saudi Arabia, Kuwait and the United Arab Emirates, are within easy missile range by Iran, lying as they do across the gulf, and so form the front line against the Islamic Republic's perceived expansionist policies.

The U.S. Defense Security Cooperation Agency says the Emirates are expected to acquire three THAAD "fire units" and 147 missiles designed to shoot down hostile ballistic weapons.

The deal also includes four radar units, six fire-control and command communications units and nine launchers, the DSCA says.

THAAD missiles don't carry warheads but are designed to destroy incoming missiles by crashing into them at altitudes up to 85 miles.

The deal is configured as a government-to-government sale under the U.S. foreign military sales program rather than one directly with Lockheed Martin. The Raytheon Corp. is also involved as it manufactures the radar units.

The THAAD acquisition would be a major boost for the Arab gulf states, which have been building up their defense forces to counter any Iranian offensive.

These states -- Saudi Arabia, the United Arab Emirates, Kuwait, Oman, Qatar and Bahrain -- form the Gulf Cooperation Council.

It is supposed to have a common defense policy but traditional rivalries between the ruling families have impeded the creation of a credible and functioning common defense network.

However, the looming threat from Iran, which is developing a substantial ballistic missile force and allegedly seeks to acquire nuclear weapons, has spurred moves by the GCC states to establish a coherent common defense system.

This still has a long way to go but introducing THAAD into the region would bolster a patchy missile defense system that currently rests largely on short-range U.S. Patriot MIM-104F PAC-3 missile systems built by Raytheon deployed in the United Arab Emirates, Kuwait, Qatar and Bahrain.

Kenneth Katzman of the U.S. Congressional Research Service, an expert in Middle Eastern security issues, says the GCC's growing fears of Iran, and U.S. efforts to bolster regional defenses have "improved the prospects for implementing a long-standing vision of a potential region-wide missile defense system."

The English-language National newspaper, published in Abu Dhabi, the Emirates' capital, reported Friday that regional defense experts who met there last week "stressed that without integrating the various missile defense systems throughout the GCC, any incoming threat could be met with an inappropriate or insufficient response."

There have been reports that the Americans want to deploy somewhere in the GCC a long-range X-band radar known as the AN/TPY-2 built by Raytheon that can detect and track missiles shortly after launch.

The idea seems to be that this high-powered unit would operate in conjunction with one set up at Israel's Nevatim Air Base in the southern Negev Desert in 2008 to boost Israel's missile defense umbrella as well as U.S. seaborne Aegis missile defenses in the Mediterranean and the gulf region.

Given the political implications of the GCC states cooperating with Israeli-based U.S. units, the issue of siting an AN/TPY-2 on the western shore of the gulf remains highly sensitive and the GCC states have shied from any public discussion of it.

Like the one in Israel, the U.S. radar would be operated by U.S. forces, which would presumably go some way toward easing GCC qualms about having to be seen to cooperate with Israel.

The combination of THAAD and the AN/TPY-2 would add a formidable addition to the GCC's efforts to establish an alliance-wide missile defense shield.

THAAD is still being developed in the United States and is scheduled to have its 14th test flight over Hawaii in July.