Iran's "irresponsible influence" in the Middle East including pursuit of nuclear weapons and support of terrorism creates a "perfect nightmare" threatening the entire region, the top US military official warned Thursday.

Admiral Michael Mullen, the chairman of the Joint Chiefs of Staff, said Iran is at the core of challenges in the volatile region, particularly its efforts in neighboring Iraq and threats against Israel.

"Iran is a regional spoiler, and is bent on egregiously undermining efforts to stabilize the Middle East," Mullen told American Jews gathered at a conference here to mark Israel's 60th anniversary.

"Their actions, their irresponsible influence extends well beyond Iraq's borders," he said. "Their pursuit of nuclear arms, their sponsorship of terrorism -- and the perfect nightmare that is the nexus of the two -- is a threat to Israel and throughout the region."

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Mullen also said the challenges of violent extremism were not exclusive to Israel and the United States; "they belong to the world, at least the world of responsible nations, to face them and overcome them."

The United States has been anchored in a prolonged "war on terror" since the September 11, 2001 attacks, and is in the sixth year of a war in Iraq in which Washington has accused Iran of training and arming insurgents.

Mullen, joined at a conference dinner by the French Prime Minister Francois Fillon, also said a resurgent Taliban was on the offensive in Afghanistan, and reiterated a call for greater international involvement there.