Bulent Tezcan, deputy leader of the CHP party, was in a stable condition in hospital following the attack in which he was shot in the leg with a handgun, the agency reported.
The incident happened in a restaurant in Aydin, southwest Turkey. Tezcan was taken to hospital shortly afterwards.
The attackers fled the scene following the incident.
The motive of the attack was not immediately known, but tensions in Turkey are soaring following a failed coup attempt in July as well as a series of attacks blamed on both outlawed Kurdish organisations as well as the Islamic State group.
Three soldiers were injured during the incident in northeast Turkey.
Tezcan was previously been injured during a brawl in the Turkish parliament in 2014.
Disclaimer: No Business Standard Journalist was involved in creation of this content