Defense Secretary Ashton Carter on Wednesday sought to assure lawmakers that the U.S. military would maintain a strong presence in the Middle East to "check Iran's malign influence" despite the the nuclear deal.
"In the face of that malign activity, we will continue to meet our commitments to our friends and allies in the region, especially Israel, and continue to build on and enhance our cooperation in meaningful ways," Carter told members of the Armed Services Committee.
He and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey appeared before the Senate panel to testify on the Iran deal, which is facing skepticism from Congress ahead of a crucial vote this fall.
Secretary of State John Kerry, Energy Secretary Ernest Moniz and Treasury Secretary Jack Lew also joined the Pentagon leaders, testifying in their third public hearing in two weeks.
Republicans and some Democrats fear the Iran deal will risk Israel's security, given that Iranian leaders have said the country "must be wiped off the map."
Carter said the U.S. would maintain its "ironclad commitment to Israel's qualitative military edge" in the region.
"We will keep providing Israel with advanced capabilities — for example, next year, Israel will be our first and only friend in the region flying the F-35 stealth fighter," he said.
He said the U.S. will also help improve the capabilities of other Gulf partners, including with its maritime forces, ground forces, special operations and counterterrorism forces, air and ballistic missile defense forces and cyber protection.
"And, we've offered sophisticated defense equipment, including the THAAD ballistic missile defense system and long-range precision strike capabilities, to some of our Gulf partners."
Carter acknowledged that Iran and its proxies would "still present security challenges."
He listed Iran's support for the Assad regime in Syria, its backing of Hezbollah in Lebanon and support for anti-government rebels in Yemen. He did not, however, mention Iran's support for Shiite militia in Iraq.
Carter said the U.S. would continue to maintain a "robust" force posture in the region, which includes tens of thousands of U.S. troops and sophisticated ground, maritime, air and ballistic missile defense assets.
Congress is expected to vote on the deal later this fall. A resolution of disapproval would prevent the White House from lifting U.S. sanctions, unless the president vetoed the resolution and Democrats sustained that veto.
Carter endorsed the agreement as "a good deal, because it removes a continued source of threat and uncertainty in a comprehensive and verifiable way by preventing Iran from getting a nuclear weapon."
"It is a deal that takes no option away from a future president. This is an important achievement and a deal that deserves your support.