Government digital infrastructure in Montenegro has been hit by an “unprecedented” cyber attack and timely measures have been taken to mitigate its impact, authorities said on Friday.

“Certain services were switched off temporarily for security reasons but the security of accounts belonging to citizens and companies and their data have not been jeopardised,” Public Administration Minister Maras Dukaj said on Twitter.

Dukaj said that the attack, which began on Thursday night, resembled several others in the past few years in the small Adriatic republic, and that Montenegro – a member of Nato – had informed its allies about it.

Online news portal Vijesti cited the National Security Agency as saying the attack was “unprecedented”.

Outgoing Prime Minister Dritan Abazovic called a session of the National Security Council for Friday evening to discuss the attack. Abazovic said it was politically motivated following the fall of his government last week.

Hackers also attacked Montenegro’s state digital infrastructure on election day in 2016, and then again over a span of several months in 2017 when the tiny former Yugoslav republic was about to join Nato.

The Western military alliance is aware of reports of cyber attacks in Montenegro and ready to help its authorities if necessary, an unidentified Nato official was quoted by the Voice of America as saying.