DURHAM, N.C. — Police have charged a man with vandalism after a paintball gun was fired at a bus in the city where tensions have been high over bus shootings.

Police said the incident occurred in the Parkwood area of Durham. The bus was hit by a yellow paintball shortly before 3 p.m. Monday.

Police said Monday the bus driver said he heard a loud thump against a window on the driver's side of the bus he was driving on Revere Road at 2:35 p.m.

Authorities say the driver was the only person on the bus and the window was not damaged

Police charged Michael Josh Spranger, 19, with vandalism and possession of marijuana.

The incident is the latest in a series of shootings involving Durham Area Transit Authority (DATA) buses. On Monday, officials underwent several changes to improve passengers' safety. DATA officials have added six security cameras and armed security guards on some of their buses.

"We will have one police officer stationed at the transfer facility. Another police officer will be riding buses and a third will actually be in a patrol car, following buses going to various areas that might need attention," said Stephen Mancuso, of DATA.

The guards will pay special attention to the No. 9 route in northeastern Durham. Buses on that route have been fired on four times since the end of March. Durham police officers riding a No. 9 bus Thursday night heard what they thought were gunshots after a group of riders got off.

Last week, city officials decided to end service at 7 p.m. on Friday and Saturday evenings on portions of the No. 9 route. Usually, the buses run until midnight. Durham Mayor Bill Bell was angered by the decision and now the buses will run on their regular schedule.

Bell, along with city officials and DATA officials, met Monday to discuss ways to improve safety on the buses. Bell said they have come up with a strategy to catch the people responsible, but he would not elaborate on those plans. He did said that the city is committing to fixing the problem.

"It is safe to ride DATA buses. That is the No. 1 message," Bell said. "The city is doing everything it can to provide security for the bus system, and we are going to find the people who are causing the problems."

Officials say the armed guards will work in conjunction with Durham police officers.