Separate packages addressed to Maryland Gov. Martin O’Malley and his secretary of transportation contained incendiary devices that flashed, smoked and produced an odor when they were opened Thursday, causing minor injuries to two employees and putting officials around the Washington region on alert.

Officials stressed that the packages were not mail bombs, and that so far they have found no explosive material associated with either of them.

The package addressed to O’Malley, which came with colorful holiday stamps, was opened about 12:30 p.m. in the mailroom of a building in downtown Annapolis.

It singed the fingers of the worker who opened it but didn’t cause any property damage.

About 15 minutes later, a similar package was opened with a flash, smoke and a sulfur smell at the Maryland Department of Transportation headquarters in Hanover.

The worker who opened it was taken to the hospital as a precaution, but again, there was no property damage.

Law enforcement officials said both packages contained notes, but they declined to say what the notes said.

Maryland officials are leading the investigation, with help from federal agen- cies.