Polish President Andrzej Duda said on Monday he will veto two of three bills reforming the country's judiciary system, easing worries that the ruling Law and Justice party will undermine the division of powers.
"I have decided that I will send back to Sejm (lower house of parliament), which means I will veto the bill, on the Supreme Court, as well as the one about the National Council of the Judiciary," Duda said after days of mass street protests.
"What we had was not a reform, but appropriation of the courts. I congratulate all Poles, this is a great success, really," Katarzyna Lubnauer, head of the parliamentary caucus of the opposition party Nowoczesna.
Polish currency, zloty, immediately rose against the euro, as investors saw the decision as lowering the political risk in Poland.
Observers say Duda's decision puts him at odds with the de facto leader of the country, Jaroslaw Kaczynski, who is the leader of PiS but has no formal government post.
The move by Duda comes after thousands of demonstrators bearing candles marched on the Polish Supreme Court on Sunday in protest against controversial proposed judicial reforms.
"Constitution, Constitution!" they chanted in front of the court building in Warsaw.
Poland's senate backed on Saturday the Supreme Court reforms, despite warnings from the European Union, appeals from Washington and massive street protests against the measures which reinforce political control over the court.
Protesters called on Duda to veto the bills.
"We want to call on the president to use his veto, even if we don't have too much hope," Karolina Chorej, a 29-year-old doctor, said.
Duda is closely allied with Poland's ruling conservative Law and Justice (PiS) party, which has pushed through the legislation.
The protesters, including many more young people than at previous rallies, held candles aloft as passages from the constitution were read out from a stage erected in front of the Supreme Court.
They also waved Polish and EU flags as well as white roses, the symbol of the civil movement against the reforms.
Similar protests were held Sunday in a hundred other Polish towns, according to media close to the opposition.
The ruling right-wing PiS party has defended the reforms, calling them indispensable to combat corruption and streamline the judicial system.
The European Union has warned the Polish government to suspend the controversial court reform effort or risk unprecedented sanctions.
The proposed reforms "would abolish any remaining judicial independence and put the judiciary under full political control of the government," European Commission vice president Frans Timmermans said last week.