Senate Armed Services Committee Chairman Sen. Roger Wicker presides over his committee's confirmation hearing on Capitol Hill in Washington, D.C., U.S., Jan. 31. AP-Yonhap

The chairs of the House and Senate Armed Services Committees have expressed concerns over the Pentagon's reported consideration of military restructuring efforts involving personnel cuts, stressing they would not accept any significant changes made without collaboration from Congress and other agencies.

Rep. Mike Rogers (R-AL) and Sen. Roger Wicker (R-MS) issued a statement Wednesday, after NBC News reported that the Pentagon is undertaking a restructuring of the U.S. military's combatant commands and headquarters, which includes the United States giving up the role of the North Atlantic Treaty Organization's Supreme Allied Commander Europe.

"U.S. combatant commands are the tip of the American warfighting spear. Therefore, we are very concerned about reports that claim DoD is considering unilateral changes on major strategic issues, including significant reductions to U.S. forces stationed abroad, absent coordination with the White House and Congress," they said in the statement.

DoD is short for Department of Defense.

They noted their support for President Donald Trump's efforts to ensure U.S. allies and partners increase their contributions to strengthen the U.S. alliance structure and for continuing America's leadership abroad.

But the lawmakers pointed out that any major changes should proceed in cooperation with Congress and other relevant agencies.

"We will not accept significant changes to our warfighting structure that are made without a rigorous interagency process, coordination with combatant commanders and the Joint Staff, and collaboration with Congress," they said.

"Such moves risk undermining American deterrence around the globe and detracting from our negotiating positions with America's adversaries."

Their statement marked a rare pushback from key Republican lawmakers. (Yonhap)