Secretary of State John Kerry on Wednesday moved to reassure Congress that Israel and America’s Gulf State allies would be fully taken care of in the wake of the Iran nuclear deal, which Kerry acknowledged would not stop Iran’s support for terrorism, according to a letter sent by the secretary of state to lawmakers.

Just moments after the White House secured enough votes to override a congressional veto of the Iran deal, a letter from Kerry appeared in the inboxes of congressional offices across Capitol Hill.

Kerry admits that, despite the deal, Iran will continue to back terrorist groups across the globe and promises to boost military support and funding to Israel and Gulf states such as Saudi Arabia, according to a copy of the letter obtained by the Washington Free Beacon.

The letter comes in response to concerns among lawmakers, Israel, and other Gulf region allies that the nuclear accord will boost the Islamic Republic’s support for terrorism, while leaving traditional U.S. allies on the defense.

"Important questions have been raised concerning the need to increase security assistance to our allies and partners in the region and to enhance our efforts to counter Iran’s destabilizing activities in the region," Kerry writes. "We share the concern expressed by many in Congress regarding Iran’s continued support for terrorist and proxy groups throughout the region, its propping up of the Assad regime in Syria, its efforts to undermine the stability of its regional neighbors, and the threat it poses to Israel."

The Obama administration, Kerry claims, is under "no illusion that this behavior will change following implementation of the JCPOA," or Joint Comprehensive Plan of Action.

"The president has made clear that he views Israel’s security as sacrosanct, and he has ensured that the United States has backed up this message with concrete actions that have increased US military, intelligence, and security cooperation with Israel to their highest levels ever," the letter states.

Kerry then goes on to outline the ways in which the Obama administration will enhance security cooperation with Israel and Gulf State allies.

Israel, for instance, will be the first country in the region to get a U.S.-made next-generation F-35 fighter aircraft in 2016.

An additional $3 billion in U.S. aid also will go to secure Israel’s missile defense programs, such as the Iron Dome system. The administration also stands ready "to enhance" funding to next-generation missile defense systems, such as Arrow-3 and David’s Sling.

The administration, Kerry writes, recently "offered Israel a $1.89 billion munitions resupply package that will replenish Israel’s inventories and will ensure its long-term continued access to sophisticated, state of the art precision guided munitions."

The administration will additionally work to secure a new 10-year "Memorandum of Understanding" with the Jewish state that "would cement for the next decade our unprecedented levels of military assistance," Kerry writes.

Kerry also proposes to collaborate with Israel on "tunnel detection and mapping technologies to provide Israel new capabilities to detect and destroy [terrorist] tunnels before the could be used to threaten Israeli civilians."

President Barack Obama has further proposed to Prime Minister Benjamin Netanyahu that the two governments "begin the process aimed a further strengthening our efforts to confront conventional and asymmetric threats."

Gulf States, such as Saudi Arabia and the United Arab Emirates (UAE), also will benefit from increased arms shipments and new security deals, according to Kerry.

The administration is "working to expedite the delivery of capabilities needed to deter and combat regional threats, including terrorism and Iran’s destabilizing activities in the region," Kerry writes.

In July, for example, the administration notified Congress of new arms sales to Saudi Arabia and the UAE "that will provide long-term strategic defense capabilities and support for their ongoing operations," the letter states.

Another goal is to strengthen ballistic missile defense capabilities in the region. This goal, Kerry says, "is a strategic imperative and an essential component to deterring Iranian aggression against any GCC member state."

One senior Congressional aide who received the letter said that it is a clear attempt by the administration to placate regional fears about the deal.

"Let’s not be fooled about what the letter represents. This desperate move to placate Israel and our Gulf partners is a tacit acknowledgment that Iran will expand its international terror regime thanks to the nuclear agreement," the source said. "If this is such a good deal, why does the administration feel compelled to immediately offer arms packages as compensation to our regional allies?"

"No amount of conventional weapons can neutralize the threat posed by the mullahs acquiring nuclear weapons," the source said. "This type of appeasement is a slap in the face to our closets allies and a wink-wink to the dictators in Tehran."