Maj. Lisa Jaster, center, embraces First Lt. Shaye Haver, left, and U.S. Army Capt. Kristen Griest, right, after an Army Ranger School graduation ceremony.

The U.S. military will open up all its positions — including frontline combat roles — to women, Defense Secretary Ashton Carter announced Thursday in a sweeping move that ends centuries of tradition.

“I am announcing my decision … to proceed with opening all these remaining occupations and positions to women,” Carter told reporters at the Pentagon. “There will be no exceptions.”

The historic move trumps a Marine Corps recommendation that said mixed-gender combat units were not as effective as men-only groups.

While acknowledging that, on average, physical differences exist between sexes, Carter said there are plenty of women who can meet rigorous physical standards — just as there are some men who cannot.

“Our force of the future must continue to benefit from the best people America has to offer,” Carter said.

“In the 21st century, that requires drawing strength from the broadest possible pool of talent. This includes women … We have to take full advantage of every individual who can meet our standards.”

President Barack Obama’s administration in 2013 asked for all combat positions to be open to women by 2016, including the infantry, artillery, armor and special forces.

But Obama gave the Pentagon the opportunity to request exceptions, provided these were justified by operational constraints.

The changes will be implemented in 30 days time, Carter said.

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