Washington (CNN) The Trump administration is expected to introduce new regulations that lawmakers say could make it easier for terrorists to get their hands on US weapons and harder to ensure they aren't used by governments known for abusing human rights.

The proposed regulations would move responsibility for licensing the export of arms that are commercially available in the US -- including assault rifles like the ones used in the Las Vegas massacre -- from the State Department, where Congress has oversight of foreign military assistance, to the Commerce Department.

Administration officials say the move, part of a reform effort that began under the Obama administration, will reduce red tape for the US firearms industry while retaining the ability to restrict sales where human rights concerns come up.

Lawmakers say the shift could leave them unable to exercise that oversight. Critics note that the guns in question, as demonstrated to tragic effect in Nevada, are known as "the real weapons of mass destruction," responsible for up to 1,000 deaths a day. In the wrong hands, they could be a threat to US troops overseas, they say.

"The Trump administration's proposed transfer of lethal weapons from the State Department Munitions List to the Department of Commerce will result in dangerous guns" being sold to countries with poor human rights records, said Sen. Ben Cardin, the top ranking Democrat on the Senate Foreign Relations Committee. "All while Congress and the American people are kept in the dark."

Cardin argues that the proposal will make it easier for "foreign despots to slaughter their civilians or for American-made assault weapons to be readily available to paramilitary or terrorist groups" through black and gray market sales.

Behind those immediate objections about the policy shift are broader concerns about the way security assistance -- by law the purview of the secretary of state, who is supposed to ensure it serves US foreign policy, not industry -- is increasingly being shifted to the Pentagon and other agencies that don't keep broader US interests in mind.

"You cannot let security assistance be driven solely by the military side," said Sen. Bob Corker, the Tennessee Republican who chairs the Foreign Relations Committee. "It's been shifting and each year we have to fend that off. If the power leans too strongly on the military side, you lose the overarching government approach to these countries."

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The Obama administration began the effort to streamline and simplify the export of defense materials, rewriting the rules for 18 out of 21 categories of export controlled defense categories. The three categories left -- categories one through three -- cover firearms, big guns such as cannons and howitzers, and munitions.

Critics say shifting oversight of these categories to Commerce could erode international curbs on exporting firearms, reduce transparency on those sales and reduce the ability of US investigators to investigate or prosecute arms smugglers. And with less visibility, it's more likely those arms could end up in the wrong hands, they say.

Lawmakers point to one planned sale of semi-automatic pistols to the bodyguard force of Turkish President Recep Tayyip Erdogan, the same group of men accused of launching a vicious attack on protestors in broad daylight in the middle of Washington.

Cardin and others successfully campaigned for the cancellation of that contract and another pending sale of "27,000 assault rifles to the Philippines national police, which continues to summarily execute its own civilians," the Maryland senator said.

"Available at any retail outlet"

"We found out about those because we have oversight now," a congressional aide said. "We would not have found out about those if they'd been on the Commerce list."

The State Department's acting assistant secretary for political-military affairs, Tina Kaidanow, told lawmakers that under the proposal, the only Category 1 through 3 arms and ammunition that would be moved from State's jurisdiction to Commerce are "the kinds of weapons that are readily available at any retail outlet in the US."

"Our strong feeling," she said, "is we want the State Department to... focus on highly sensitive technologies where either our commercial edge or our troops will be endangered overseas through the spread of these weapons."

State Department officials say that oversight of military grade weaponry in the three categories won't be moved to Commerce. And they say that Congress could still exercise oversight with Congress overseeing the arms exports. There will be an interagency review of sales and the State Department will be able to continue to restrict them where needed, they say.

They point to an executive order that directs Commerce, to the extent required by statute or regulation, to notify Congress about the export of firearms.

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But there are no statutes or regulations requiring Commerce to notify Congress of firearms exports, congressional aides point out. And it's not clear when, exactly, lawmakers would be notified: before an export license is approved, before the actual export, or after the transaction has taken place.

Adding to concern is that fact that the Commerce Department's oversight is "notoriously less robust than the State Department's," wrote Rachel Stohl, director of the Conventional Defense Program at the Stimson Center, and Colby Goodman, director of the Security Assistance Monitor at the Center for International Policy, in a recent opinion piece on the issue in Defense News.

Kaidanow told lawmakers in late September that "we believe strongly that the most important, most sensitive weapons, the ones that you would concern yourself on a regular basis, again military grade weapons, that's the kind of thing that the State Department should continue to exercise its control."

Mass casualty events

Previous attempts to shift oversight of Category 1 through 3 arms were delayed after mass casualty events such as the Sandy Hook shootings in Connecticut, where one man killed 20 children and six adults at an elementary school, officials in Congress and at the State Department say.

The Las Vegas massacre, where one man killed 58 people and injured another 527 in just a few minutes may cause the administration to rethink this latest attempt to shift oversight, some aides suggested. While the weapons don't seem to have the lethality of larger weapons or weapons systems, their impact can still be deadly.

"These are the things that more often kill people on a daily basis, they're easier to proliferate, use in every day in human rights atrocities," an aide said.