WARSAW, Poland (AP) — The former top European Union leader who recently took the helm of Poland's strongest opposition party appealed Tuesday for a “non-aggression pact” among the opponents of the country's right-wing government.

Donald Tusk, a former Polish prime minister who served as president of the European Council, met with Senate Speaker Tomasz Grodzki, a political ally, and is holding talks with various party leaders and political figures on strengthening the opposition. Grodzki is a member of the pro-EU Civic Platform party, which Tusk co-founded in 2001 and resumed the leadership of on Saturday.

Tusk said that while unity should not be expected in all areas, Poland's opposition forces should avoid conflict among them.

“It will not be easy at all to build a unity on every level, on every issue, so at least (let's have) an honest and respected from today non-aggression pact, which means that if we have a difference of opinion, we can talk about it, but we do not attack each other within the opposition camp,” he said.

Tusk did not name anyone, but Szymon Holownia, the founder of the Poland 2050 party, has said that he sees Tusk's return to Poland's politics as a challenge that will help the opposition party consolidate and develop.

In a June opinion poll, Holownia's Poland 2050 received more support than Tusk's party. The ruling right-wing nationalist coalition of the Law and Justice party and two small partners leads the polls.

When retaking his party leadership Saturday, Tusk said he was returning to Poland’s politics with the intention of fighting the “evil” caused by the Law and Justice-led government, which has ruled Poland since 2015 and put the country on a collision course with the EU.

Tusk said that due to his involvement in Polish politics, he will not seek reelection as president of the European People's Party, which fields candidates for the EU Parliament.

The Associated Press