BERLIN - The federal prosecutor's office in Germany said it was investigating who was responsible for a spate of hacking attempts aimed at lawmakers, amid growing concerns that Russia is trying to disrupt the Sept 26 vote for a new government.

The move by the prosecutor's office on Friday (Sept 10) comes after Germany's Foreign Ministry said this week that it had protested to Russia, complaining that several state lawmakers and members of the federal Parliament had been targeted by phishing e-mails and other attempts to obtain passwords and other personal information.

Those accusations prompted the federal prosecutor to open a preliminary investigation against what was described as a "foreign power".

The prosecutors did not identify the country but did cite the Foreign Ministry statement, leaving little doubt that their efforts were concentrated on Russia.

In their statement, the prosecutors said they had opened an investigation "in connection with the so-called Ghostwriter campaign", a reference to a hacking campaign that German intelligence says can be attributed to the Russian state and specifically to the Russian military intelligence service known as the GRU.

Russia was found to have hacked into the German Parliament's computer systems in 2015, and three years later it breached the German government's main data network.

Chancellor Angela Merkel protested over both attacks, but her government struggled to find an appropriate response, and the matter of Russian hacking is now especially sensitive, coming in the weeks before Germans go to the polls to select a successor after her nearly 16 years in power.

Moscow denied it was involved in the hacking efforts. "Despite our repeated appeals through diplomatic channels, our partners in Germany have not provided any evidence of Russia's involvement in these attacks," the Russian Foreign Ministry spokesman, Maria Zakharova, said at a briefing on Thursday.

She called the German allegations "an extraordinary public relations story", and said the suspicions appeared to be the work of "individual politicians" intent on showing they would "not allow gaps in trans-Atlantic solidarity", in an apparent reference to Germany's strong ties with the United States.

Germany's Foreign Ministry spokesman Andrea Sasse said on Wednesday of the hacking attempts: "The German government regards this unacceptable action as a threat to the security of the Federal Republic of Germany and to the democratic decision-making process, and as a serious burden on bilateral relations. The federal government strongly urges the Russian government to cease these unlawful cyber activities with immediate effect."

Merkel is not running for re-election and will leave office after a new government is formed, meaning the election will be crucial in determining Germany's future - and shaping its relationship with Russia.

Of the three candidates most likely to replace Dr Merkel, the Greens' Annalena Baerbock, who has pledged to take the toughest stance against Moscow, has been the target of the most aggressive disinformation campaign.

The other two candidates - Mr Armin Laschet of Dr Merkel's Christian Democratic Union, and Mr Olaf Scholz of the Social Democrats, currently Dr Merkel's vice-chancellor and Finance Minister - have served in three of the four Merkel governments, and neither is expected to change Berlin's relationship to Moscow.

Dr Merkel enacted tough economic sanctions against Moscow after the 2014 invasion of Ukraine despite some pushback in other capitals and at home, but she has also worked hard to keep the lines of communication open with Moscow.

The two countries have significant economic links, not least in the energy market, where they most recently cooperated on construction of a direct natural gas pipeline, which the Russian energy company Gazprom announced had been completed Friday.

US intelligence agencies believe that "Ghostwriter", a Russian program that received its nickname from a cyber-security firm, was active in disseminating false information about the coronavirus before the 2020 US presidential election, efforts that were considered to be a refinement of what Russia tried to do during the 2016 campaign.

But attempts to meddle in previous German election campaigns have been limited, partly because of respect for Dr Merkel but also because the far-right and populist parties that have emerged in France and Italy have failed to gain as much traction in Germany.