WASHINGTON (AP) — The Latest on Congress' consideration of a new war authority for U.S. troops (all times local):

7:15 p.m.

Congressional Democrats are pressing senior national security officials on whether there are circumstances that would allow President Donald Trump to preemptively strike North Korea or another country with nuclear weapons.

Sen. Edward Markey of Massachusetts is asking Defense Secretary Jim Mattis and Secretary of State Rex Tillerson if Trump could launch a "first strike" without consulting any members of Congress.

Defense Secretary Jim Mattis is avoiding a direct answer, saying the question is hypothetical. But Mattis says he could imagine a scenario where it's possible if another country were preparing to fire weapons of mass destruction at the United States.

Mattis also says the process for launching nuclear weapons is very rigorous.

Tillerson says no U.S. president "has foresworn first strike and that has served us well for 70 years."

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5:30 p.m.

Senior U.S. national security officials say a new war authorization is "not legally required" to conduct combat operations against terrorist groups.

Secretary of State Rex Tillerson and Defense Secretary Jim Mattis testified Monday before the Senate Foreign Relations Committee, three months after they informed the panel a post-Sept. 11, 2001, law gave the military ample authority to fight terrorist groups and a new one was unnecessary.

A separate authorization for the war in Iraq approved by Congress in 2002 also remains in force.

Tillerson and Mattis say that if Congress does pursue a new authorization for foes such as the Islamic State, it's imperative that the existing law not be rescinded until the new one is fully in place.

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2:02 p.m.

U.S. Secretary of State Rex Tillerson plans to tell lawmakers that the administration doesn't believe a new war powers resolution is necessary.

But Tillerson will say that if Congress does pursue a new authorization, it's imperative that the 2001 law that currently authorizes U.S. troops to fight terrorist groups not be rescinded until the new authorization is fully in place.

A State Department official says Tillerson will also emphasize that any new war authorization, like the existing one, should not have any geographic or time restrictions placed on the use of force. The official wasn't authorized to discuss the arguments ahead of the hearing and requested anonymity.

Sen. Ben Cardin in particular has pushed for restrictions to be built into any replacement resolution. Cardin is the top Democrat on the Senate Foreign Relations Committee, where Tillerson and Defense Secretary Jim Mattis are testifying on Monday.

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12:50 p.m.

A Democratic senator says the ambush in Niger that killed four American soldiers underscores the need for Congress to urgently approve a new war authorization.

Sen. Chris Coons of Delaware says the United States has "gone far afield" from the scope of the 2001 authorization that passed shortly after Sept. 11 and sanctioned operations against al-Qaida.

During an appearance on CNN, Coons says most members of Congress weren't even in office when the authorization for the use of military force was signed into law by former President George W. Bush.

Coons says it would have been difficult to imagine 16 years ago that U.S. soldiers would be killed in West Africa by Islamic State militants "based on an attack that was launched in 2001 from Afghanistan thousands of miles away."

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3:29 a.m.

President Donald Trump's national security brain trust is set to testify on the need for a new war authorization as the deadly ambush in Niger ignites a push among lawmakers to recast the legal parameters for combat operations overseas.

Defense Secretary Jim Mattis and Secretary of State Rex Tillerson will testify before the Senate Foreign Relations Committee on Monday. They told the panel behind closed doors three months ago that a 2001 law gave the military ample authority to fight terrorist groups.

But that's a position that won't wash with a growing number of congressional Republicans and Democrats. They're arguing the dynamics of the battlefield have shifted dramatically and it's well past time to replace the post-Sept. 11 authorization with a law that reflects current threats.