Mateusz Kijowski, leader of the KOD pro-democracy movement | Janek Skarzynski/AFP via Getty Images Polish opposition leader hit by cash conflict Mateusz Kijowski is the most-visible challenger to PiS government in rule of law debate.

The head of Poland’s anti-government protest movement admitted Thursday to using the organization's funds to pay his IT business, handing the ruling party an easy line of attack against one of its main foes.

The onet.pl portal and Rzeczpospolita newspaper reported Wednesday that the MKM Studio company, owned by Mateusz Kijowski and his wife, billed the Committee for the Defense of Democracy (KOD) 91,000 złotys (about €20,000) for computer services.

Kijowski said on Facebook Thursday that the bills sent to KOD were genuine, admitting that “Maybe I didn’t have enough experience and carefulness, but I vow that there was no dishonesty.” He later told reporters the work was aimed at securing KOD's websites from attacks by hackers, and that his company is no longer working for KOD.

He called the reports a "provocation" and said he wasn't quitting as leader.

However, the allegations swirling around Kijowski are a boon to the ruling Law and Justice party (PiS). The government is embroiled in a fight with opposition parties, which are staging a sit-in in parliament to protest a budget passed in questionable circumstances as well as rules (since changed) restricting journalists’ access to the legislature.

Ryszard Terlecki, the deputy speaker of parliament and a PiS MP, said the issue of Kijowski’s bills made the opposition look “ridiculous,” telling Polish media that it “discredited everyone who in recent months worked with this grouping.”

Mariusz Błaszczak, the interior minister, called the issue “very strange,” accusing Kijowski of turning KOD into a private business.

Kijowski and KOD have become the most visible challengers to Law and Justice at a time when the parliamentary opposition is fractured and doesn’t have the votes to stop the ruling party’s initiatives, which opponents say risk undermining Polish democracy.

The KOD movement was founded in late 2015 to oppose Law and Justice, using a similar name and principles to groupings that had worked against the Communist Party before 1989.

Kijowski, a computer programmer, quickly rose from obscurity to head the movement. In recent years, he was a sporadically employed IT specialist who blogged mainly on post-divorce fathers’ rights.

Since then, he’s been a charismatic presence at anti-government protests, the most recent of which were held outside the parliament buildings in Warsaw over the Christmas holidays.

In the wake of the reports, Grzegorz Schetyna, leader of Civic Platform, the largest opposition party, called on KOD and Kijowski to be open about the group’s finances.

“Financial questions, especially in a group like KOD and with Mateusz Kijowski, must be transparent,” Schetyna told reporters.