Democrats in the US House of Representatives have demanded the Trump administration publicly acknowledge Israel's undeclared nuclear weapons program.

In a letter to US Secretary of State Marco Rubio, 30 Democrats said Tuesday that Washington cannot develop a coherent nonproliferation policy for the Middle East while maintaining a policy of official silence about the program amid the US-Israeli war on Iran.

"We are, in the fullest sense, fighting this war side by side with a country whose potential nuclear weapons program the United States government officially refuses to acknowledge," wrote the lawmakers, led by Congressman Joaquin Castro.

"The risks of miscalculation, escalation, and nuclear use in this environment are not theoretical," they said.

The Democrats argued that Congress "has a constitutional responsibility to be fully informed about the nuclear balance in the Middle East, the risk of escalation by any party to this conflict, and the administration's planning and contingencies for such scenarios."

They asked for details on Israeli nuclear weapons capabilities, including warheads and launchers, enrichment capabilities, and what Washington has been told about Israeli red lines.

Israel neither confirms nor denies possessing nuclear weapons, and the White House has maintained ambiguity on Israel's nuclear program over the decades.

A policy of ambiguity on Israel's nuclear program "makes coherent nonproliferation policy in the Middle East impossible, for Iran, for Saudi Arabia, and for every other state in the region making decisions based on their perceptions of the capabilities of their neighbors," the Democrats wrote.