The commission's conclusion comes despite Tusk, who was prime minister from 2007 to 2014, being widely predicted to return to his old post as head of government.
The current government faces a vote of confidence on December 11 in a Polish parliament dominated by the opposition. A failure to win will give the opposition, led by Tusk, a chance to form the next government.
According to the commission, its preliminary findings show that poor supervision of the Military Counterintelligence Service (SKW) at the time when Tusk was prime minister led to "improper activities being carried out by the SKW."
Along with Tusk, the commission also said a number of other people who had positions in the Tusk-led government should not hold public office linked to security.
The others named were: Jacek Cichocki, interior minister 2011-2013; Bogdan Klich, defence minister 2007-2011; Tomasz Siemoniak, defence minister 2011-2015, and Bartlomiej Sienkiewicz, who was interior minister 2013-2014.
"The Commission recommends not entrusting them with tasks, positions and public functions related to responsibility for state security," Andrzej Zybertowicz, a commission member, said on Wednesday.
"When analysing the available materials, including the testimony of the above-mentioned people during the prosecutor's office investigation, we had the impression that politicians responsible for state security were not interested in state security and that this scope of their responsibility was not a priority for them," he added.
A review of Polish energy policy and of the influence of the Russian Federation on the media and foreign policy is also urgently needed, Zybertowicz continued.
Slawomir Cenckiewicz, the chairman of the commission, told a Wednesday press conference that the body had decided to focus on cooperation between the SKW and the Federal Security Service (FSB) of the Russian Federation in 2010-2014.
According to Andrzej Kowalski, a commission member and a former head of the Military Intelligence Service (SWW), who listed the main theses of the commission's preliminary report, the cooperation between the SKW and the FSB from April 2010 to December 2011 "was carried out without the formal consent of the prime minister and without the knowledge of the defence minister, and is confirmed in documents."
He said that, under the Act on the Military Counterintelligence Service and the Military Intelligence Service, the consent to cooperate with a foreign secret service is given by the prime minister "but after seeking the opinion of the minister of national defence" and that "it must be a written consent."
Kowalski added that having examined a great deal of state documents, the commission concluded that it was "very probable" that "there was Russian influence on the operation of Polish military counterintelligence."
According to one thesis, he continued, the "SKW succumbed to the influence of the Federal Security Service, with the consent of the state leadership, including the consent of Prime Minister Donald Tusk."
Kowalski also said that Gen. Janusz Nosek, the head of the SKW, had been tightening contacts with the FSB since 2010, and this led to the signing of an agreement between the SKW and the FSB in St. Petersburg on September 13, 2013 on cooperation and collaboration in the area of military counterintelligence.
According to the commission, the agreement was harmful "in terms of being in conflict with the obligations of the Republic of Poland towards Nato."
"One of the provisions of the agreement signed with the FSB clearly put us in a situation where we would inform them about the Nato operations against Russia known to us. A very dangerous situation, a dangerous circumstance and one that actually harms allied interests," Kowalski said.
Cenckiewicz added that the report must only be regarded as partial owing to the commission being restricted to less than three months work because of an opposition motion to have its members dismissed.
He also said that a limited report on the commission's work to date, consisting of about 100 pages, will be published on the Prime Minister's Office website after the press conference.
He said that the report was based on public non-confidential materials. "Some of them were declassified literally a few hours ago," he added.
The law establishing the commission, originally initiated by politicians of the governing Law and Justice (PiS) party, came into force on May 31.
PiS was also the only political grouping to nominate their candidates for the commission, which was established in late August.
Its task was to establish whether any politicians were operating under Russian influence in the years 2007-2022.
Critics feared, in particular, the commission could be used to prevent opposition leader Tusk from running in the October 15 elections. (PAP)
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