A trio of Senate Democrats on Friday pressed President Trump to explain his rationale and legal justification for a potential military strike against Syria following last week’s reported chemical weapons attack.

“This issue is of critical importance and the American people should be fully informed about your rationale for deploying American military power and the objectives of any U.S. military action in Syria,” the senators wrote in a Friday letter to Trump. “As previous commanders-in-chief have done in similar situations, we believe you should present a clear public articulation of these matters to the American people at the earliest appropriate time.”

{mosads}The letter was signed by Sens. Jack Reed (D-R.I.), ranking member of the Senate Armed Services Committee; Dick Durbin (D-Ill.), Senate minority whip and vice chairman of the Defense appropriations subcommittee; and Bob Menendez (D-N.J.), ranking member of the Senate Foreign Relations Committee.

The senators join a growing list of Democrats who have expressed concern in recent days about Trump overstepping his authority with a strike on Syria.

The Trump administration is weighing military action after the latest chemical weapons attack blamed on Syrian President Bashar Assad. Last weekend, horrific images emerged of the dozens killed and hundreds injured in the attack in the Damascus suburb of Douma.

Trump appeared to indicate a U.S. strike was imminent earlier this week in a tweet warning Assad-backer Russia to “get ready” because missiles “will be coming, nice and new and ‘smart!’”

But his administration has since walked that back, saying Thursday that no decision has been made yet as they weigh how extensive the operation should be and any potential consequences, such as killing Russians.

Meanwhile, administration officials and most Republicans have said Trump has the legal authority to conduct a “surgical” strike in Syria without congressional authorization.

In their letter, Reed, Durbin and Menendez said the world is “rightly horrified” by Assad’s “continuing abuse and murder.” But, they added, taking a military action is a “momentous decision.”

“In recent days, you have publicly signaled your intent to undertake military action in response to the alleged chemical weapons attack this past weekend,” they wrote. “The use of U.S. military capabilities to conduct offensive action against another nation is a momentous decision that poses serious risks to the lives of U.S. military personnel involved and the possibility of escalation into a broader conflict.”

Administration officials asserting legal authority for a strike, they said, have done so “without explaining the underlying legal basis for their assertion.”

“Given your public statements and those of other members of the administration related to potential military action in Syria, we ask that you promptly provide the legal basis for any potential or anticipated military action in response to the alleged use of chemical weapons by the Syrian regime in Douma on April 7,” the senators wrote. “As part of your response, we also ask that you fully explain any limiting principles on the use of the U.S. military to conduct military action absent a specific authorization for the use of military force by the Congress.”