WARSAW, Poland (AP) — Poland's ruling conservative party has requested a recount of votes to six Senate seats after losing its control of that chamber in the country's recent election.

Law and Justice spokesman Radoslaw Fogiel said the party is exercising its right to a recount in districts where the vote was close and where there were many invalid votes. It filed its requests for the recount to the Supreme Court on Monday.

The party's critics voiced fears that Law and Justice was seeking to reverse the election results of the Oct. 13 election.

Grzegorz Schetyna, leader of centrist opposition party Civic Platform, on Tuesday called it a "big scandal" and called for an international observation by the Organization for Security and Cooperation in Europe of any recount. He said he had no certainty that the votes would be counted in a transparent way.

"Law and Justice does not accept the electoral verdict; it does not accept the will of Poles, who with very high voter turnout put the majority of the Senate in the hands of opposition parties," Schetyna said. "This is an example that shows how elections look and how the next elections will look when Law and Justice does not win."

Law and Justice kept control of the more powerful lower house. However, opposition parties won 51 seats in the 100-seat Senate. That would give them the power to slow down the passage of the ruling party's legislation, but not block it, and to keep Law and Justice from appointing its loyalists to head key state bodies.

The request for the partial vote recount comes after Law and Justice reportedly tried to win over opposition politicians who won Senate seats in a bid to create a majority there, but none agreed.

Law and Justice won power in 2015 and immediately set about reshaping the judicial system in a way that gives the party greater control over the courts. The European Union has repeatedly warned that the changes threaten rule of law in the young democracy.

A recount of the vote would include the involvement of a new chamber at the Supreme Court, established by Law and Justice, whose constitutionality has been questioned by Europe's leading human rights body, the Council of Europe.

The OSCE, which observed the campaign, said the elections were essentially free and well run, but that the ruling party had an unfair advantage thanks to its control of public media.