Washington(CNN) Two leading Senate Democrats are calling on President Donald Trump to declassify the formal notification given to Congress regarding the US drone strike that killed Iranian military commander Qasem Soleimani.
It's not publicly known what exactly is in the formal notification, though such messages to Congress typically explain legal justification for military action.
"It is critical that national security matters of such import be shared with the American people in a timely manner," says the letter, authored by Senate Minority Leader Chuck Schumer and Sen. Bob Menendez, the top Democrat on the Senate Foreign Relations Committee. "An entirely classified notification is simply not appropriate in a democratic society, and there appears to be no legitimate justification for classifying this notification."
The letter comes as Trump on Sunday signaled that he wouldn't rule out releasing some of the intelligence amid lingering skepticism from lawmakers and the public about whether the strike was justified.
"We may discuss that," he said when questioned aboard Air Force One.
Top US national security officials have continued to defend the Trump administration's claim that it killed Soleimani in response to an impending threat to American lives, but questions have continued to swirl over the timing and legality.
One Democratic source who was briefed Friday by administration officials said the information offered was "absolutely unconvincing" as far as proving there was an imminent threat. And in an interview with CNN last week, Democratic Sen. Tom Udall of New Mexico said more than once that he does not believe an attack on the United States was imminent as Trump and other top administration officials have said.
"My staff was briefed by a number of people representing a variety of agencies in the United States government and they came away with no feeling that there was evidence of an imminent attack," Udall said.
A Republican congressional source familiar with the administration's decision to strike Soleimani acknowledged that in the past, the President "has been reluctant to take military action." In this case, the killing of an American contractor, the wounding of others, and the subsequent embassy protests "crossed his line." His advisers also pointed out to the President that if he "didn't respond now, they (Iran) will continue to cross it."
"I am very confident he was not reluctant," said the source. When Trump finally gets ready to act, they added, "you can't out escalate him."
CNN has previously reported that there was internal debate over the decision and work behind the scenes to develop a legal argument before the operation was carried out.
CLARIFICATION: This story has been updated to better describe what Senate Democrats want declassified.