Military helicopters, conducting a military training exercise, fly past the Statue of Liberty in this photograph taken from Liberty State Park in Jersey City, New Jersey, U.S., March 11, 2017. REUTERS/Ashlee Espinal

WASHINGTON (Reuters) - Incidents of unwanted sexual contact increased by nearly 50 percent at top U.S. military academies over the past two years, according to a Pentagon survey released on Thursday, highlighting an issue that has long plagued the military.

The study, part of a report released annually, said there had been 747 instances of unwanted sexual contact in 2018, compared to 507 in 2016.

Sexual assault and harassment in the U.S. military is largely under-reported and came under renewed scrutiny two years ago after a scandal involving Marines sharing nude photos of women online came to light.

The survey said that 16.5 percent of female cadets at the U.S. Military Academy at West Point experienced unwanted sexual contact in 2018, compared to 10.2 percent in 2016.

All cadets at West Point as well as a Navy and Air Force academy were given the opportunity to take part in the survey.

In a statement, the Army said it had directed West Point to create a plan in the next few weeks to tackle the issue.

“There is no room in the U.S. Army for sexual harassment or sexual assault,” the statement said.

“This is a readiness issue that affects our ability to prepare to fight and win our Nation’s wars as much as it is an issue of values,” it added.