KABUL, Afghanistan — An explosion went off Tuesday in front of a military hospital in Kabul, causing casualties, a Taliban official said.

Interior Ministry spokesman Saeed Khosty wrote in a tweet that the blast went off at one of the gates to Sardar Mohammad Dawood Khan military hospital. The number of casualties is unknown, he wrote. He added that special forces were on the scene.

There was no official confirmation of a second explosion that had been heard in the area of the hospital in the 10th district of Kabul. Area residents said they also heard the sound of gunfire.