Defense Secretary Ash Carter outlined Tuesday several broad changes he envisions to make the Pentagon more efficient in combating global threats such as the Islamic State group.

Speaking at the Center for Strategic and International Studies, a Washington think tank, Carter suggested updates to parts of the Goldwater-Nichols Act, a sweeping 1986 Pentagon reform law that restructured America's vast military.

Borne from lessons learned during the Vietnam War and the botched 1980 Iranian hostage rescue mission, the act sought to soothe rivalries and fix a lack of cooperation between the services.

Observers say the historic reforms need updates to reflect the changed nature of 21st century threats and warfare.

For instance, Carter said he wants to clarify the role of the chairman of the joint chiefs of staff, the Pentagon's top officer who serves as the defense secretary's principal adviser.

"More steps (are needed) to strengthen the capability of the chairman and the joint chiefs to support force management, planning, and execution across the combatant commands, particularly in the face of threats that cut across regional and functional combatant command areas of responsibility," Carter said.

Despite the extra influence of the chairman, a position currently held by General Joe Dunford, Carter said the role would remain outside of the Pentagon's direct chain of command, which currently flows from the president to the defense secretary to the relevant commanders.

Carter also called for simpler military acquisition processes and a greater coordination between various combatant commands, such as Africa Command and European Command, to deal with trans-regional threats such as the IS group.

He suggested each command could become more efficient if fewer four-star generals worked at the head of each organization.

"Billets currently filled by four-star generals and admirals will be filled by three-stars in the future," he said.

The Pentagon can execute some of its proposals under its own authority, and will do so in the "coming weeks," Carter said. Other decisions will need congressional approval.