In an extraordinary development late on January 9, Polish police entered the offices of President Andrzej Duda and detained two former PiS MPs, Maciej Wasik and Mariusz Kaminski, under arrest warrants following their recent conviction for abusing power in a corruption case from over 10 years ago.

The arrest signifies a sudden rise of political tension in Poland, where the new government, headed by Donald Tusk, promises to “restore rule of law”, which it says was compromised by PiS  tinkering with the judiciary system, poor lawmaking, and the creation of institutions of questionable legal status.

Duda's defence of the two convicted MPs also confirms that he has decided to be a staunch opponent of the new government, perhaps with a view to eventually taking over as PiS leader, rather than taking a compromise position in the hope of landing a top international job.

Despite remaining on-site in the presidential palace, the police managed to detain Wasik and Kaminski to the uproar of PiS, which flooded social media with claims of a “coup” being underway and Poland’s “first political prisoners since communism”.

A small rally in solidarity with the detainees took place outside a police headquarters in Warsaw, where Wasik and Kaminski were held before being moved to custody.

The former home affairs and administration minister Kaminski and his deputy Wasik, were sentenced to two years in prison for abusing their power as heads of Poland’s anti-corruption force CBA in 2007.

President Duda pardoned the pair in 2015, but some legal experts disputed the pardon because Duda granted it before an earlier court sentence against the two MPs became legally binding.

Following the December conviction and the issue of arrest warrants, a political and legal row erupted over the status of Wasik and Kaminski, with the government claiming they must be stripped of their MP mandates.

Citing "de-escalation", the parliament's Speaker Szymon Hołownia postponed this week's parliament sittings in order to avoid a potential scuffle with the convicted MPs if they tried to enter the plenary session.