WASHINGTON — The Senate’s top Democrat, Senate Minority Leader Chuck Schumer, said he favors a re-examination of the country’s legal authorizations to wage war amid controversy surrounding the deaths of four U.S. troops in Niger.

The comments came days after the Senate Foreign Relations Committee announced it will hold a long-awaited debate on the nation’s two authorizations for the use of military force, or AUMFs. Defense Secretary Jim Mattis and Secretary of State Rex Tillerson are set to testify in the Oct. 30 open hearing about whether the nation needs an updated AUMF.

“We are in a brave new world. You know, there are no set battle plans. You don’t declare war and fight three weeks later,” Schumer, of New York, told NBC’s Chuck Todd on Sunday.

“But having said that, the Constitution says Congress has the power to declare war. And if you’re in a long-term war, Congress ought to keep that ability. So we need to re-examine this. We are on an AUMF that extends 16 years from right after we were attacked at the World Trade Center. So I would be for re-examining it. Absolutely.”

Controversy swirling around the deaths of U.S. troops in Niger, the president’s interactions with the troops’ families and whether the administration is being forthcoming about operations there has fueled talk on Capitol Hill about the president’s legal authorization to wage war.

Senate Armed Services Committee Chairman John McCain, R-Ariz., said last week he was open to a subpoena to get answers from the administration about the troop deaths. On Sunday, South Carolina Republican Sen. Lindsey Graham told Bloomberg TV he and McCain would receive a briefing on Niger this week.

“Sen. McCain is frustrated, rightly so,” Graham said. “We don’t know exactly where we’re at in the world, militarily, and what we’re doing. So John McCain is going to try to create a new system to make sure that we can answer the question why we were there. We’ll know how many soldiers are there, and if somebody gets killed there, that we won’t find out about it in the paper.”

The Trump administration relies on authorizations from 2001 and 2002 for the current military campaign against the Islamic State group as well as other contingencies around the globe.

However, lawmakers have wrestled with a new AUMF for years. The Trump administration is not seeking a new AUMF, but members of Congress argue the old ones do not provide a sound legal basis for current operations.

Last month, the Senate voted 61-36 to scuttle aproposalfrom Sen. Rand Paul, R-Ky., to repeal the authorizations.

Schumer said Sunday he agreed with Paul “that we ought to look at this carefully.”

Most recently, a bipartisan group of veterans on the House Armed Services Committee offered a replacement AUMF earlier this month. One of the co-sponsors, Arizona Democratic Rep. Ruben Gallego, an Iraq veteran, hoped there would be new momentum and bipartisan support for the proposal this week.

“For one, there are a lot of members of Congress who were surprised we have troops in Niger, and the reason they’re surprised is with an expansive AUMF, there are no checks and balances, and there is no reason for [the administration] to come and talk to you,” Gallego said.

“We should find a responsible way to curtail not just the president but the Department of Defense to wage war without end, without oversight from Congress — which is our duty under the Constitution.”

Sen. Tim Kaine, who has co-authored a replacement AUMF with Arizona Republican Sen. Jeff Flake, said Friday: “The many questions surrounding the death of American service members in Niger show the urgent need to have a public discussion about the current extent of our military operations around the world.”

Tillerson and Mattis informed lawmakers in August that the 2001 authorization provides sufficient authority to wage war against ISIS in Iraq and Syria. But Tillerson and Mattis also said they’re open to an updated authorization, provided the measure doesn’t impose tactically unwise restrictions or infringe on the president’s constitutional powers as commander in chief.