Pro-opposition gunmen stormed the station.
One of the gunmen locked in a protracted stand-off in a police station in the Armenian capital Yerevan shot an officer dead today, a police spokesman said.
"A sniper opened fire from inside the police station and killed a police officer ... who was sitting in a car parked 350-400 metres (yards) away," Ashot Aharonyan wrote on Facebook.
The shooting came after police threatened to break up the standoff, which began on July 17 when pro-opposition gunmen stormed the station, killing an officer and taking several hostages.