Finland's Foreign Ministry says a Finnish aid worker who was kidnapped in Afghanistan in May has been released.

The ministry said on September 14 that the woman was working for a Swedish aid group in Kabul called Operation Mercy.

A statement on the aid group's website confirmed the woman's release, saying that "the well-being of our colleague is being assessed at this time."

Afghanistan's Interior Ministry said a German woman who also worked for Operation Mercy was shot dead on May 20 when the kidnappers attacked the nongovernmental organization's Kabul residence.

An Afghan guard at the guest house for aid workers was beheaded by the attackers.

With reporting by Reuters and CNN