Officials say a drone has dropped a package of drugs into a US prison yard while inmates were outside, sparking a fight.

The package was dropped last week at the Mansfield Correctional Institution in Ohio state. A corrections official told a local newspaper that it contained almost 7 grams of heroin, 57 grams of marijuana and 140 grams of tobacco.

Officials say video footage shows the drone over recreation yards immediately before a fight began. An investigation determined the drone dropped a package intended for an inmate on the north recreation yard, and it was thrown over a fence to the south recreation yard.

The inmates were separated and searched. No injuries were reported.