Fortifying one of its key allies in the Persian Gulf, the Obama administration announced a weapons deal with Saudi Arabia on Thursday, saying it had agreed to sell F-15 fighter jets valued at nearly $30 billion to the Royal Saudi Air Force.

The agreement, and the administration's parallel plans to press ahead with a nearly $11-billion arms deal for Iraq, despite rising political tensions there, is dramatic evidence of its determination to project U.S. military influence in an oil-rich region shadowed by a threat from Iran.

Although the White House said the deal had not been accelerated to respond to threats by Iranian officials in recent days to shut off the Strait of Hormuz, its timing is laden with significance, as tensions with Iran have deepened and the United States has withdrawn its last soldiers from Iraq.

“This sale will send a strong message to countries in the region that the United States is committed to stability in the gulf and the broader Middle East,” said Andrew J. Shapiro, the Assistant Secretary of State for political-military affairs. “It will enhance Saudi Arabia's ability to deter and defend against external threats to its sovereignty.”

The agreement also suggests that the United States and Saudi Arabia have moved beyond a falling-out over the uprisings in the Arab world. Although the two countries continue to differ on how to handle the popular revolts in the region, U.S. and Saudi officials said, the disagreement has not fractured a strategic alliance based on a common concern over Iran.

Saudi Arabia is a longtime foe of Iran, with relations souring further last fall after the United States broke up what it said was an Iranian-backed plot to kill the Saudi Ambassador to Washington. Iran has denied the accusations.

“When you look at the size of this package, what does it tell you about U.S.-Saudi relations?” said a senior Saudi official, who spoke anonymously because he was not authorised to speak publicly. “It says it's very strong and very solid. Any disagreements from time to time don't affect the core relationship.”

The weapons package is remarkable, both for its size and technical sophistication. Under the terms of the $29.4-billion agreement signed Saturday, Saudi Arabia will get 84 new F-15SA jets, manufactured by Boeing Co., and upgrades to 70 F-15s in the Saudi fleet with new munitions and spare parts. It will also get help with training, logistics and maintenance.

The new F-15s, which will be delivered in 2015, are among the most capable and versatile fighter jets in the world, Pentagon officials said. They will come with the latest air-to-air missiles and precision-guided air-to-ground missiles, enabling them to strike ships and radar facilities day or night and in any weather.

Although Mr. Shapiro and other officials said the planes were intended to help Saudi Arabia protect its sovereignty, military analysts said they would be effective against Iranian planes and ships anywhere in the Persian Gulf.

They are part of a 10-year, $60-billion weapons package for Saudi Arabia that was approved last year by Congress. — New York Times News Service

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