London, Dec 7 (IANS): The UK has accused Russia's security service, the FSB, of a sustained cyber-hacking campaign, targeting politicians and others in public life, media reports said on Thursday.

The government said one group stole data through cyber-attacks, which was later made public, including material linked to the 2019 election, the BBC reported.

Russia has repeatedly denied claims it is involved in such activities.

Foreign Secretary David Cameron said the group's actions were "completely unacceptable", BBC reported.

"Despite their repeated efforts, they have failed. We will continue to work together with our allies to expose Russian covert cyber activity and hold Russia to account for its actions," the former Prime Minister said.

Foreign Office Minister Leo Docherty told the House of Commons on Thursday that Russia's Ambassador has been summoned and two individuals were being sanctioned. One of them is a serving FSB officer, BBC reported.

The group is accused of carrying out hundreds of highly targeted hacks against politicians, civil servants, those working for think-tanks, journalists, academics and others in public life. These mainly targeted the private emails of individuals following extensive research and the creation of false accounts impersonating their trusted contacts.

The Federal Security Service (FSB) is the successor agency to the KGB, which operated throughout the Cold War.

Russian President Vladimir Putin was its director for a period in the 1990s.

The group linked to the FSB - and specifically the part of it known as Centre 18 - has been targeting the UK by stealing information from those in political and public life since at least 2015, it is believed, BBC reported.

It is claimed the group remains active.

The US is also expected to announce action against the group.

"Russia is targeting the UK's democratic process," Western officials said.

However, the campaign has been judged not to have been successful in interfering in the democratic process.

Thursday's public accusation is aimed at disrupting the group's work and increasing awareness ahead of major elections around the world next year, BBC reported.