BALTIMORE (AP) — The city of Baltimore will be monitored by surveillance airplanes for up to six months next year under a pilot program announced Friday that authorities say is aimed at helping law enforcement investigate crime.

The flights will start in May and gather footage for between four and six months, during a time of year when the city usually experiences the most violence, Baltimore Police Commissioner Michael Harrison said at a news conference.

The resolution of the footage won't be sharp enough for officers to identify faces, but should help them track movement and action, Harrison said.

Harrison had previously opposed the use of the planes. He said he now believes they could prove to be “yet another tool” to fight violence plaguing the city.

The three planes will fly simultaneously, gathering footage over 90 percent of the city, said Baltimore police spokesman Matt Jablow.