Twenty-one Opposition parties on Wednesday filed a review petition in the Supreme Court asking it to direct the Election Commission to cross-check at least 50% votes using Voter Verified Paper Audit Trail slips, say reports. The third phase of Lok Sabha poll voting ended on Tuesday.

The petitioners cited concerns raised in the first two phases of voting in the Lok Sabha polls, News18 reported.

Earlier this month, the Supreme Court had ordered that Voter Verified Paper Audit Trail slips of five electronic voting machines in every constituency be counted instead of just one EVM in the ongoing elections. The court had said this practice will ensure the “greatest degree of accuracy, satisfaction” in the election process. The court passed the order on a petition filed by Opposition parties who sought direction to verify at least 50% of the votes cast in the Lok Sabha elections using the VVPAT machines.

The Election Commission had earlier filed an affidavit in the top court citing logistical difficulties in verifying 50% VVPAt slips, which would delay the announcement of results by six days.

The parties that have approached the court include the Congress, Andhra Pradesh Chief Minister Chandrababu Naidu’s Telugu Desam Party, Sharad Pawar’s Nationalist Congress Party, Aam Aadmi Party, Communist Party of India (Marxist), Communist Party of India, Derek O’Brien for the Trinamool Congress, Farooq Abdullah for the National Conference, the Samajwadi Party, the Bahujan Samaj Party, the Rashtriya Lok Dal, Sharad Yadav’s Loktantrik Janata Dal, and the Dravida Munnetra Kazhagam.

Opposition parties have raised doubts about the credibility of electronic voting machines a number of times in the last two years. However, the Election Commission has repeatedly denied allegations that the machines can be tampered with.

On January 24, Chief Election Commissioner Sunil Arora reiterated that the country would not revert to using ballot papers for elections.

The Lok Sabha elections are being held in seven phases until May 19, and the results will be declared on May 23.