Police spokesman Ashot Agaronyan says on Facebook the gunmen were the first to open fire Friday.
A group of 29 gunmen seized the police post in Yerevan on July 17, killing one officer and wounding several others in the attack, to demand freedom for a jailed opposition figure. In addition to the three gunmen wounded Friday, five others were wounded in previous exchanges of fire with police.
The gunmen also are still holding hostage three members of an ambulance crew who were providing treatment to two wounded attackers who remained inside the station.