A small power plant in Britain shut down during a cyberattack that took place last month. The government said that at no point was there any danger to the country’s energy system, but in any case the Department for Energy Security has contacted power generation companies in the country to warn them about the risk of cyberattacks.

The Telegraph reported that “hackers affiliated with the Iranian government” carried out the attack.

For security reasons, neither the government nor the UK National Cyber Security Centre, which is responsible for tackling attacks on critical infrastructure, has provided further details about the affected site. However, according to the report, the incident was not an attack on a main power grid plant such as a large power station.

But according to The Telegraph, the power plant had been out of operation for four days.

The Department for Energy Security said that the incident affected a small power generation unit and that at no time was there any danger to the country’s broader energy system.

Britain’s power grid has a number of small gas power plants that are used on short notice when needed to supply electricity.