Istanbul succumbed to a string of lengthy power outages last week. Authorities say the outages were linked to physical sabotage on the grid and acknowledged they also faced a significant cyber-attack.

Speaking to A Haber TV on Friday, Energy and Natural Resources Berat Albayrak confirmed the attacks but the energy supply security does not face any substantial risk.

Albayrak said they stepped up security on the electricity grid upon increasing tip-offs regarding the potential attacks in recent days and stated the latest instance of such an attack was a U.S.-based cyber-attack on Thursday. "Different centers of the ministry are systematically targeted in cyber-attacks but we managed to fend them off. We have no significant risk related to production in terms of energy supply security," the minister stated.

Authorities have been quiet about the exact cause of the power outages and Albayrak said their investigation led to findings regarding the sabotage. "We shared the findings with prosecutors and coordinate the investigative work with the Interior Ministry in light of increasing incidents. We take extra security measures (for the power grid) not only for Istanbul but other cities. We have to be vigilant against sabotage," he said. Albayrak also noted some suspects were detained in connection with the attacks on power lines. He said detainees sabotaged power grids in three different locations in Istanbul and the sabotage involved cutting off the cables and "different actions," although he did not elaborate.

The minister said seven main power lines were cut off simultaneously from the grid for the first time, leaving "a serious damage on the system." He said four out of seven lines were restored to the grid.

On cyber-attacks, Albayrak said they received a tip-off on Dec. 30 for a New Year's Eve attack and their measures prevented it.