Serbian police say they arrested 15 suspected radical Islamists, on Saturday, a day after a gunman who is believed to have ties to a radical group opened fire at the U.S. embassy in neighboring Bosnia.

Serbian interior ministry officials say the suspects were arrested during raids in three towns in southwestern Serbia with large Muslim communities. They say the raids targeted supporters of the Wahhabi movement, a strict, conservative branch of Islam that is dominant in Saudi Arabia.

On Friday, a gunman identified as Mevlid Jasarevic opened fire and wounded a police officer at the U.S. embassy in the Bosnian capital Sarajevo before he was wounded by a police officer and arrested.

Authorities say he is from the region where Saturday's raids were conducted and is believed to be a follower of Wahhabism.

Meanwhile, police have stepped up security around the embassy.

A U.S. State Department spokeswoman said Friday that an outer wall of the building was damaged, but that no one inside was hurt. She praised local authorities for a swift response.

The reason for the shooting was not immediately clear.

Bosnia was the scene of a bloody ethnic conflict in the early 1990s between its Croat, Muslim and Serb communities.

During the conflict, many radical Islamists from Muslim countries came as volunteers to support Bosnian Muslims and brought Wahhabism to the Balkans.

Most Bosnian Muslims are protective of their relationship with the United States because it supported a NATO intervention to end the fighting and brokered the 1995 peace agreement.