The U.S. on Monday launched airstrikes against the Islamic State (ISIS) in Libya, expanding its war in the region in what the Pentagon indicated will be a long-term offensive against the militant group and what critics said was a "deeply" concerning move.

Rep. Barbara Lee (D-Calif.) said Monday that she was "deeply concerned about the expansion of U.S. airstrikes in Libya. The U.S. military continues to become more engaged in the Middle East, despite the lack of a Congressional debate or specific authorization."

"The American people and our brave men and women in uniform deserve a public debate on this war, including the costs and consequences to our national security and domestic priorities. They deserve a Congress with the courage to debate the war that we are asking them to fight," Lee said.

"Our military experts are clear: there is no military solution to this crisis," she continued. "Only a comprehensive, regionally-led strategy that addresses the underlying political, economic, humanitarian and diplomatic challenges will be effective in ultimately degrading and dismantling [ISIS]."

The strategic port city of Sirte was hit by strikes from manned drones and other aircraft, with "additional" bombings to come, Pentagon press secretary Peter Cook said. While the U.S. has hit areas in Libya before, this marks the first step of a sustained operation, the Guardian reports.

Glenn Greenwald tweeted in response:

1st bombing campaign of Libya was such a grand success that it only took 5 years for the 2nd one to happen https://t.co/aidT0qvJXX — Glenn Greenwald (@ggreenwald) August 1, 2016

Monday's actions came at the request of the United Nations-backed Libyan Government of National Accord (GNA) and had been approved by President Barack Obama, the Pentagon said.

Military Times reports on the scale of the operation:

The attack Monday was part of a comprehensive series of operations planned and controlled by AFRICOM. The first element of this three-phase plan is Operation Odyssey Resolve, consisting of intelligence, surveillance and reconnaissance flights designed to counter violent extremism in Libya. The second phase, Operation Junction Serpent, provided targeting information. The third element, Operation Odyssey Lightning, includes strike aircraft hitting those targets. That operation reportedly began over the weekend, Pentagon sources said.

Journalist David Mizner noted:

What a surprise, the government that the US & co. imposed on #Libya is requesting that the US bomb Libya. https://t.co/Y4cgAVDX5n — David Mizner (@DavidMizner) August 1, 2016

The strikes come as Politico separately reports that the military is angling to "defeat" the group by the November 8 U.S. election, although officials insist the timing is coincidental.

"Hurrying this thing along for political benefit would be just about the dumbest thing that we could do," a senior CENTCOM official told Politico's Mark Perry.

Perry writes:

U.S. officials have confirmed the Pentagon is planning ways to time their offensive against Mosul with an attack on the Islamic State "capital" in Raqqa, Syria. A coordinated Mosul-Raqqa military offensive could yield a dual defeat to the ISIS caliphate, unhinge ISIS power in both Syria and Iraq and have the added benefit of pinning ISIS units moving into Iraq along interior lines from Syria in place. [....] The ambitious plans for Mosul and Raqqa reflect a shift in tactics and deeper U.S. involvement that has not been fully reported in the U.S. media—or talked about in the presidential campaign.

"The bad news is that while the broad U.S.-led coalition to fight ISIS remains unified, the same cannot be said for the forces on the ground. The only thing that unites them, it seems, is that they hate ISIS more than they hate each other. So while senior U.S. military officers are confident that a final assault on Mosul will succeed, they also know that the offensive could break apart even before it is launched," Politico's Mary Perry writes. "Which means that while Obama would welcome an October surprise, he continues to caution that the fight against ISIS could take years."