Changes to recruit training could be coming, Commandant Gen. Robert Neller told lawmakers Tuesday in a tense session about the ongoing investigation into whether Marines viewed nude pictures of female troops, veterans and civilians and harassed those women.

A spokesman for Neller, Lt. Col. Eric Dent, declined to say whether the evaluation of recruit training to which Neller referred may include desegregating boot camp, so that men and women would be integrated during the 13-week program.

"He said we are looking at changes," Dent told Marine Corps Times after the hearing. "Nothing to report on yet other than we are looking at how we conduct recruit training to see if there are ways to improve."

Neller, Sergeant Major of the Marine Corps Ronald Green and Acting Navy Secretary Sean Stackley were grilled for more than two hours during an open Senate Armed Services Committee hearing before briefing lawmakers in a closed session on Tuesday.

About 500 people of the 30,000-member Marines United Facebook community are believed to have viewed the nude pictures, said Neller, who added the Marine Corps' policy on social media is being updated to more directly address cyber bullying.

The nude photos on the members-only Marines United site has set off a criminal investigation into whether Marines wrongfully posted photos of naked female Marines and subjected them to online harassment. Other services are also investigating similar sites allegedly involving other service branches. 

Sen. Elizabeth Warren said the misogynistic and possible illegal behavior seen on "Marines United" and other websites is symptomatic of larger problem that starts at boot camp.

"Are you willing to reconsider the role that Marine recruit training plays in this and re-evaluate the Marine Corps' policy of gender segregation at basic training?" Warren, D-Mass., asked.

The Marine Corps is taking a "very long look at how we do recruit training," said Neller, who did not address whether any specific changes are being considered. He also took issue with Warren's characterization of boot camp as segregated.

"We're not separating men and women anymore in the Marines?" Warren asked.

Male and female recruits from all of the services live separately because they are lodged in open squad bays, Neller said, but at Marine Corps Recruit Depot Parris Island in South Carolina, both male and female recruits conduct "a good portion" of their training together," including the Crucible, the grueling 54-hour capstone to boot camp.

"To say, that we're segregated, I don't believe is a fair statement," Neller said. "But we do it differently than everybody else."

But when Warren pressed Neller on the matter, he conceded that male and female Marine recruits do train separately during parts of boot camp.

"We are looking at the entire way that we do recruit training from how we educate and train our drill instructors to how we do the entire program of instruction for men and women," Neller said.

On Jan. 1, 2016, then-Navy Secretary Ray Mabus had ordered the Marine Corps to completely integrate recruit training, but Corps leadership ultimately persuaded him to allow male and female recruits to continue to train separately for some events.

"The Marines did a very good job of showing ... that the way it's done now sets both men and women up for greater success," Mabus told Marine Corps Times on Feb. 2, 2016.

However, the Service Women's Action Network is advocating for the Marine Corps to follow the Army, Navy and Air Force by fully integrating all boot camp training. 

"The Marine Corps is the only service that segregates men and women at basic training," SWAN said in a March 6 statement. "Women Marines are physically separated from men and held to different and lower training standards. This creates and perpetuates an 'us versus them' environment where women are viewed as a lesser category of Marine and ultimately results in high levels of harassment and assault."