The Pentagon announced Friday that it has reached a preliminary agreement on a complex $10 billion arms deal with Israel, Saudi Arabia and the United Arab Emirates, in what would represent the latest major weapons sale to U.S. allies in the Middle East.

Defense Secretary Chuck Hagel will attempt to finalize the arms package next week when he is scheduled to visit the three countries. Ultimately, the deal will need the assent of Congress. Defense officials said they have kept lawmakers apprised of the negotiations and revealed basics of the agreement to lawmakers on Thursday.

Under terms of the deal, the United States would deliver V-22 Osprey transport aircraft, KC-135 refueling planes and anti-radiation missiles to Israel; about two dozen F-16 warplanes to the UAE; and advanced aircraft missiles to the Saudis and the Emiratis. News of the pact was first reported Friday by the New York Times.

U.S. officials indicated that the weapons are designed to boost each country’s military capabilities in the event of a conflict with Iran. “The common threats that we, the Israelis, Saudis and Emiratis, have are clear,” a senior defense official told reporters at the Pentagon on the condition of anonymity because the deal has not received final approval.

The Pentagon did not provide a country-by-country dollar breakdown of the sales, but said the agreement is unprecedented for the Middle East because it was negotiated simultaneously.

U.S. officials said the White House wanted to ensure that Israel retained a “qualitative military edge” in the region, while at the same time improving Saudi and UAE defenses. Like the United States and Israel, the two Arab countries suspect that Iran is trying to develop nuclear weapons and they consider that the biggest threat facing the Middle East.

In the past, Israel has discouraged some U.S. weapons sales to Saudi Arabia, fearing that its military advantage might erode. By negotiating the $10 billion package simultaneously with each country and offering reassurances along the way, the Pentagon was able to forestall any objections, officials said.

Although the monetary value of the agreement is large, previous deals have been bigger. In 2010, the Pentagon agreed to sell Riyadh $30 billion worth of F-15 fighter jets. In 2011, it signed a deal to sell $3.5 billion in missile-defense systems to the UAE.

Israel receives more annual U.S. military aid than any other foreign country. The White House has proposed giving Israel $3.4 billion next year.