PLUSH, Ore. (AP) — Federal and state agencies are investigating if there was a link between a series of wildfires in southeastern Oregon and military training exercises.

Officials believe the seven small fires that ignited on July 11 could have been connected because they were all attributed to human activity, Oregon Public Broadcasting reported (http://bit.ly/2tKJHKe ).

In addition, remains of an incendiary flare used in the military training exercises were found at one of the burn sites, the state Department of Forestry said. The Oregon National Guard agreed to suspend the use of the flares after investigators contacted officials. But National Guard spokesman Maj. Stephen Bomar said he was skeptical his agency was the source of the fires.

"It has been more than 20 years without any sort of flare starting a fire at all in this air space," Bomar said, adding that the flare found was military grade but did not match those used by Oregon's National Guard.

In 2015, the U.S. Department of Interior, the U.S. Environmental Protection Agency and Oregon's Department of Fish and Wildlife all warned of potential wildfire risk from flare use, citing species such as sage grouse that could be threatened by loss of habitat from wildfire. All three agencies asked the Air National Guard to restrict its use of flares during periods of "high" fire danger, rather than just during "extreme" fire danger.

Fire danger currently ranges between high and very high throughout most of Eastern Oregon.

Brett Fay, assistant regional fire management coordinator for the U.S. Fish and Wildlife Service, said last week's concentration of ignitions was "pretty rare."