WASHINGTON (AP) — The Trump administration has adequate legal authority to combat terrorist groups and doesn’t support a push in Congress for a new law permitting military action against the Islamic State and other militants, a senior White House official said Tuesday.

The comments Tuesday by White House legislative director Marc Short came as Republican Sen. Rand Paul of Kentucky ramped up pressure on his colleagues to reassert their power to decide whether to send American troops into harm’s way. Paul, a leader of the GOP’s non-interventionist wing, wants a vote on his amendment to the annual defense policy bill that would let the authorizations after the Sept. 11 attacks lapse after six months. He says Congress would use the time to pass a new war authority.

Many congressional Republicans and Democrats have been clamoring for Congress to approve a new authorization for the use of military force. But they’re moving too slowly for Paul, who’s demanding the deadline to ensure faster action.

Paul said on Monday evening he would use his senatorial power to block amendments from other lawmakers to the $700 billion defense policy bill unless his measure was considered.

“Where is the anti-war left demanding the wars end? Where is the constitutional conservative right demanding Congress reclaim its war powers?” Paul declared on his Twitter account. He later said unidentified Senate leaders had “agreed to four hours of debate under my control to debate these wars.” It was unclear, however, if that would culminate with a vote on his amendment.

To fight the Islamic State group, the Trump administration, as did the Obama administration, relies on an authorization for the use of military force that was approved by Congress in 2001, shortly after the Sept. 11 attacks.

But the White House’s use of an authorization from a decade and half ago is a legal stretch at best, according to critics who’ve argued for years that Congress needs to pass a new one to account for how the dynamics of the battlefield have changed. For example, American troops are battling an enemy — Islamic State militants — that didn’t exist 16 years ago in a country — Syria — that the U.S. didn’t expect to be fighting in.

A separate authorization for the war in Iraq approved in 2002 also remains in force.

The War Powers Resolution, enacted in 1973, requires the president to tell Congress he is sending U.S. troops into combat and prohibits those forces from remaining for more than 90 days unless Congress has approved an authorization for military force.

Secretary of State Rex Tillerson and Defense Secretary Jim Mattis informed lawmakers last month that the 2001 authorization provides sufficient authority to wage war against the Islamic State 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.

But Short, who spoke at a Christian Science Monitor breakfast, said the administration isn’t looking for changes and stood by the 2001 authorization.