Germany's cyber security chief was fired after allegations that he was too close to Russians.
Arne Schönbohm has been the head of the Federal Cyber Security Authority (BSI) which since 2016 is in charge of protecting government communications.
German media accused Schönbohm of having ties to people involved with Russian intelligence services.
The Home Office is investigating the allegations against him, but confirmed he had been sacked with immediate effect.
Before leading BSI, Mr. Schönbohm had helped create and mode of the Cybersecurity Council in Germany, a private association that advises businesses and policymakers on cybersecurity issues.
He is said to have maintained close links with the club and attended their 10th anniversary celebrations in September.
One of the members of the association was a cyber security company called Protelion, and it turned out to be a subsidiary of a Russian company allegedly founded by a former member of the KGB who was honored by the President Vladimir Putin.
Protelion was kicked out of the club last weekend, and Germany's Cyber Security Council said claims of links to Russian intelligence were untrue.
A spokesman for Interior Minister Nancy Faeser appeared to confirm that Mr Schönbohm's dismissal came in response to the recent reports, saying:
“The background to this is the allegations that were exposed and widely discussed in the media. The necessary public trust in the neutrality and impartiality of his leadership as chairman of Germany's most important cyber security agency has been damaged."
But they stressed that the security chief will be presumed innocent while the allegations are investigated.
Germany's Der Spiegel reported that Mr Schönbohm had himself requested formal disciplinary proceedings against him, after there was no reaction from the government after the first accusations.
The Berlin on the other hand, it appears increasingly concerned that its critical infrastructure could be targeted by Russian intelligence as it steps up its support for Ukraine.
Last week, the Ministry of Defense announced plans to deliver four air defense systems to Kiev. A unit IRIS-T is said to be capable of defending an entire city from air attacks.
