AeroVironment Inc. has secured a nearly $6 million contract to provide its Raven drones to the Portuguese army, the Monrovia unmanned aircraft manufacturer has announced.

Delivery on the drones will occur over a three-year period. AeroVironment develops, manufacturers and tests its unmanned aircraft in Simi Valley.

“The Raven system will provide the Portuguese Army with rapid and effective force protection as well as interoperability capabilities with NATO forces, supporting coalition mission integration,” Kirk Flittie, vice president and general manager of AeroVironment’s unmanned aircraft systems division, said in a statement.

Portugal is the 18th of 29 NATO member nations to purchase AeroVironment drones. The company announced the deal last week.

Shares of AeroVironment (AVAV) closed Monday up 31 cents, or a fraction of a percent, to $116.82 on the Nasdaq.