Polish Prime Minister Donald Tusk said Sunday a man accused of plotting an assassination attack against him and defence minister had been detained, following an earlier announcement of suspected threats from the interior ministry.

"The man threatening an attack has been detained," Tusk wrote on X, praising the police for their "swift and decisive action".

The arrest was also confirmed on X by Polish Interior Minister Marcin Kierwinski.

Earlier, the interior ministry said Tusk and Defence Minister Wladyslaw Kosiniak-Kamysz may have been targeted by assassination attempts.

A "report about a potential assassination attempt on Prime Minister Donald Tusk, as well as on Deputy Prime Minister and Minister of National Defence Wladyslaw Kosiniak-Kamysz, was transmitted to the police via the State Protection Service (SOP)", interior ministry spokeswoman Karolina Galecka said at a press briefing.

Earlier on Sunday, the ministry ordered authorities to take action "in connection with the information received by (the police) concerning a possible assassination attempt on the prime minister... as well as the deputy prime minister", who is also defence minister, Galecka wrote on X.

Members of the police, state protection service (SOP) and internal security agency were present at the meeting Sunday.

"We are treating this matter as deadly serious," a spokesperson for the minister-coordinator of special services, Jacek Dobrzynski, told journalists afterwards.

"Month by month, year by year, more and more various threats and menacing messages reach the police, SOP, and the services concerning Poland and Poles," he said, adding that "in this case we are talking about a strong likelihood that these threats could actually be carried out".

Poland, a NATO and EU member country, has been on high alert following multiple stabbing attacks in the last week, which Tusk on Thursday denounced as a "cult of violence".