A UN mission was set up in 1993
to oversee the uneasy ceasefire
Eight masked gunmen abducted a group of eight UN military observers from the Kodori gorge, said world body officials in Georgia.
Four Russian peacekeepers were later released and immediately reported the incident.
Three peacekeepers and their interpreter are still being held captive.
Germany’s defence ministry confirmed that two of the UN monitors were its nationals. UN officials confirmed the third peacekeeper is Danish.
The assailants, who were not identified, opened fire on a truck carrying members of a joint patrol of UN observers and Russian peacekeepers. There were no reports of injuries.
Earlier, local officials reported than eight UN observers were abducted as they conducted a patrol of the buffer zone which separates Georgian forces from Abkhaz rebels.
The Monitors from the UN Observer Mission in Georgia (UNOMIG) are charged with supervising a ceasefire between Georgia and Abkhazia.
The UN mission, which included 114 observers as of 1 January, was set up in 1993 to oversee an uneasy ceasefire between Georgian government forces and separatists from the Abkhazia region.
Nine people, including five UN observers and their translator, were killed in October 2001 when their helicopter was downed by a missile as it flew over the Kodorsky gorge.
The UN mission resumed work in February 2002.
The former autonomous republic of Abkhazia, northwest of Georgia, obtained detained de facto independence from Tbililsi after bitter fighting in 1992-1993.
Its government is not recognized by Georgia or any foreign government. The separatists want full independence and UN-sponsored peace talks have stalled.
About 250,000 Georgians were forced to flee Abkhazia in the war, which ended after Georgian forces withdrew from the region and the establishment of UNOMIG in September 1993.
Georgian and Abkhazian officials had been expected to sign an agreement on the return of ethnic Georgian refugees to the breakaway region on Thursday, reported Interfax news agency.
The situation deteriorated following an incursion of Chechen rebels into the region in October 2001 which led to the deployment of Georgian and Abkhaz troops into the Kodori gorge border zone.