The White House sent Congress on Saturday a formal notification under the War Powers Act of the drone strike ordered by President Trump this week that killed Maj. Gen. Qassim Suleimani, two congressional officials said.

The notification, required by law within 48 hours of introducing American forces into armed conflict or a situation that could lead to war, has to be signed and then sent to Congress, according to the officials with knowledge of the plan.

Lawmakers expected the document to publicly lay out the White House’s legal justification for the strike on General Suleimani, Iran’s top security commander, who officials have said has been behind hundreds of American deaths over the years. But the notification first sent to Congress late Saturday afternoon only contained classified information, according to a senior congressional aide, likely detailing the intelligence that led to the action. It is unclear whether the White House will send a separate, unclassified document.

Speaker Nancy Pelosi said in a statement Saturday evening that the notification “raises more questions than it answers,” including “serious and urgent questions about the timing, manner and justification of the administration’s decision to engage in hostilities against Iran.”