Secretary of Defense Chuck Hagel said on Sunday that weapons sales to the United States’ allies in the Middle East send a “very clear signal” to Iran that they might use military means to prevent it from building a nuclear weapon.

“The bottom line is that Iran is a threat, a real threat,” the secretary, who was appointed by President Barack Obama in February, told reporters before landing in Israel.

The Jewish state, believed to be the region’s only nuclear power, has repeatedly expressed its impatience with the failure of Western diplomatic efforts to dissuade the Iranians from enriching uranium. The Islamic republic claims that the purpose of its nuclear program is to generate electricity.

Saudi Arabia and neighboring Arab Gulf states, allied to the United States, nevertheless share Israel’s concerns. Prince Turki bin Faisal Al Saud, the kingdom’s former intelligence chief, warned in late 2011 that his country might seek a nuclear capacity of its own if Iran attains it.

Hagel’s trip comes two days after the Defense Department announced it was finalizing agreements to seal air defenses, refueling tankers and troop transport planes to Israel as well as F-16 fighter jets to the United Arab Emirates.

The United States previously sold and upgraded F-15 fighter planes and attack helicopters to Saudi Arabia while the UAE bought a $3.6 billion missile interception system from Lockheed Martin. The Gulf Cooperation Council states are in talks to mount a joint missile defense.

More than half of $56 billion worth of American weapons sales in 2011 was linked to Saudi Arabia.

Oman, Saudi Arabia and the United Arab Emirates are also in talks with Britain’s BAE Systems to buy nearly $10 billion worth of Typhoon fighter jets. The Saudis already operate 72 of such planes.