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Women had not been allowed to participate in certain military roles last year

The women joining the Marines as infantry graduated from the the School of Infantry

Washington CNN  — 

An infantry battalion at Camp Lejeune in North Carolina received three historic additions Thursday – the first women infantry Marines.

The three women will serve in the 1st Battalion, 8th Marine Regiment, with specializations as rifleman, machine gun and mortar, according to 1st Lt. John McCombs, a Marines spokesman.

The identities of the women are not being released at this time to allow them to get acclimated to their unit, McCombs said. The unit already has three females in leadership roles and they will be able to help with the transition, he noted.

Women had not been allowed to participate in certain military roles until Defense Secretary Ash Carter announced that starting in January 2016, the military would be required to open all combat positions to both males and females.

Women have been working to fight alongside men for more than 150 years, according to the US military – going as far back as the Civil War where more than 400 women disguised themselves as men.

As a new administration readies to take over, it is unclear how Donald Trump will handle the role of women in the military.

In August 2015, Trump told CNN’s Chris Cuomo he would allow women to fight in the military because “they’re really into it,” but said he would also want to speak to the military about the issue.

Trump tweeted a comment in 2013 that appeared to raise doubts about women serving. “26,000 unreported sexual assaults in the military-only 238 convictions. What did these geniuses expect when they put men & women together?” Trump wrote.

When asked about the remark during a campaign forum in September, Trump stood by it. “I think that that’s absolutely correct,” Trump told NBC’s Matt Lauer.

Trump clarified that he did not think the solution was to take women out of the equation completely. “But something has to happen,” Trump said. “Right now, part of the problem is nobody gets prosecuted. You have reported … you have the report of rape and nobody gets prosecuted.”

Trump’s nominee for defense secretary, retired Gen. James Mattis, has made comments suggesting he is wary about female integration into infantry and special operations roles where there is what he called “intimate killing.”

“When you have to reduce standards – as you would have to do, you would have to do it – and when you would mix, you know, when you mix eros, when you mix affection for one another that could be manifested sexually, I don’t care if you go anywhere in history, you will not find where this has worked. Never has this worked,” Mattis said in 2015.

“We have had numerous cases where you have put healthy young men and women together and you expect them to act like little saints,” Mattis added.

On Wednesday, Mattis met with New York Democratic Sen. Kirsten Gillibrand to talk about the value of women in the military.

When Gillibrand was asked if she had any policy disagreements with Trump’s nominee, she responded: “I do have concerns about the role of women in the military and how sexual assault in the military will be addressed, but I’ll ask those questions in the hearing specifically so he can answer them for the record and then make a decision.”

Gillibrand has been a fierce advocate of military sexual assault prevention legislation in Congress and has worked to change how reports of sexual assaults are handled.

CNN’s Ryan Browne and Daniella Diaz contributed to this report.