American aid to Israel is illegal under a decades-old law that prohibits aid to nuclear powers that have not signed the international Nuclear Non-Proliferation Treaty (NPT), according to a lawsuit filed in federal court in Washington, DC.

The lawsuit, filed this week by Grant Smith, the director of the Institute for Research: Middle Eastern Policy, comes as the US and Israel have closed many of the gaps in negotiations over a new 10-year military aid package worth tens of billions of dollars.

Discussing the lawsuit in an interview with Court House News, Smith said the US has provided Israel an estimated $234 billion in foreign assistance since Congress passed the International Security Assistance and Arms Export Control Act in 1976, which bans aid to non-signatories of the NPT that posses nuclear weapons.

In addition to the US, the August 8 litigation names President Barack Obama, Secretary of State John Kerry, CIA Director John Brennan, Defense Secretary Ashton Carter, and the secretaries of the Treasury, Energy and Commerce Departments as defendants.

“Defendants have collectively engaged in a violation of administrative procedure and the Take Care Clause by unlawful failure to act upon facts long in their possession while prohibiting the release of official government information about Israel’s nuclear weapons program, particularly ongoing illicit transfers of nuclear weapons material and technology from the US to Israel,” the 33-page lawsuit states.

This screen capture shows Grant Smith, the director of the Institute for Research: Middle Eastern Policy

Smith said that the US government threatens federal employees and researchers with prosecution, fines, and imprisonment in order to maintain its policy of “nuclear ambiguity” regarding Israel’s nuclear weapons program.

The gag is driven by a Department of Energy directive known as WNP-136, Foreign Nuclear Capabilities. Smith said he has obtained a highly-redacted version of the directive under the Freedom of Information Act.

“This is an Energy Department directive that demands imprisonment for any federal official or contractor who even mentions that Israel might have a nuclear weapons program,” he said in the interview.

The US has maintained a long-standing policy of keeping silent on Israel’s nuclear arsenal, which is widely believed to contain hundreds of nuclear warheads.

Washington has been providing the Israeli regime with $3.1 billion annually since a 2007 agreement with the administration of former president George W. Bush.

Israel has indicated that it wants $4 billion to $4.5 billion in aid as part of a new deal that will go into effect from 2018.

US military assistance to Israel has amounted to $124.3 billion since it began in 1962, according to a recent congressional report.