KABUL, Afghanistan (WCMH/AP) – The president of the American University in the Afghan capital says a militant attack is underway on the campus.

Mark English tells The Associated Press that security forces are on the scene after Wednesday’s attack and that “we are trying to assess the situation.”

Witnesses say they heard explosions and automatic gunfire. It was not immediately clear if anyone was wounded.

Police spokesman Sediq Sediqqi says police and intelligence agency personnel are at the campus, on the western outskirts of Kabul. He says police believe there is just one assailant.

“We have been notified of a complex attack on the American University on Darul-Aman Road,” the commander of Kabul police’s quick reaction force told NBC News, adding, “We still don’t know the exact nature of the attack.”

Pulitzer Prize-winning photographer Massoud Hossaini tweeted that he was at the complex and heard shooting and an explosion:

The attack comes two weeks after two university staff were kidnapped from their car by unknown gunmen. Their whereabouts are still unknown.

American University of Afghanistan opened its doors in 2006 as Afghanistan’s first independent university. Today, it enrolls more than 1,700 full and part-time students.Keep checking NBC4i.com for real-time updates on this story. To get alerts for breaking news, grab the free NBC4 News App for iPhone or Android. You can also sign up for email alerts.