Updated at 7:19 p.m. ET
Congressional Democrats are promising to act this week to limit President Trump's ability to unilaterally order military action against Iran.
In a letter to House Democrats, Speaker Nancy Pelosi, D-Calif., called last week's drone airstrike against Iranian Maj. Gen. Qassem Soleimani "provocative and disproportionate," saying the strike "endangered our servicemembers, diplomats and others by risking a serious escalation of tensions with Iran."
Pelosi said the House will vote later this week on a resolution under the War Powers Act to prevent Trump from acting against Iran after 30 days unless Congress votes to authorize further military operations.
The measure is likely to pass in the Democratic-controlled House, but a similar proposal failed in the Senate last year.
Meanwhile, Senate Minority Leader Chuck Schumer, D-N.Y., called on the Trump administration to immediately declassify the White House notification to Congress about the airstrike that killed Soleimani.
Schumer and the top Democrat on the Senate Foreign Relations Committee, Sen. Robert Menendez, D-N.J., wrote that it is "critical for the Trump administration to share additional information with the American people" about the military operation. The pair criticized Trump for classifying the entire notification, saying "there was no legitimate justification for such extensive classification."
Speaking to reporters Monday morning, White House adviser Kellyanne Conway accused Schumer and Menendez of "chest thumping."
"They know that Congress will be briefed. It could start as recently as this week. But that's up to the Pentagon," Conway said.
The actions come as lawmakers return to the Capitol from their midwinter break. President Trump returned to Washington on Sunday night after spending the holidays at his home in Florida.
Top administration officials are scheduled to brief all senators on Wednesday on Iran, according to two Senate aides. All House members are also expected to receive a similar closed-door briefing Wednesday.
Secretary of Defense Mark Esper, Secretary of State Mike Pompeo, CIA Director Gina Haspel and Chairman of the Joint Chiefs of Staff Mark Milley will conduct the closed-door briefings, according to the aides.
Eight Senate leaders, known as the "gang of eight" are expected to be briefed Tuesday afternoon.
Congressional correspondent Kelsey Snell and congressional reporter Claudia Grisales contributed to this report.