ERBIL, Iraq (Reuters) - The ruling Kurdistan Democratic Party (KDP) was leading in a parliamentary election in the semi-autonomous Kurdistan Region of Iraq with 85 percent of votes counted, the election commission said on Thursday.

A year after a failed bid for independence, Iraq’s Kurds voted on Sunday in a parliamentary election that could disrupt the delicate balance of power in the region.

With 85 percent of ballots counted, the KDP was leading with 595,592 votes, the Independent High Elections and Referendum Commission (KHEC) said in a news conference.

Its historic rival and junior coalition partner in government, the Patriotic Union of Kurdistan (PUK), was in second place with 287,575 votes.

The commission said it had received and was investigating 1,045 complaints, which is why it had not published final results.

On Sunday, the PUK said it might not recognize the results of the election due to what it described as violations in the voting process, and then appeared to backtrack, injecting uncertainty into the process.

Election observers also said there were irregularities.

With opposition parties weak, the KDP and PUK are likely to extend their almost three decades of sharing power, but the preliminary results suggest that Masoud Barzani’s KDP will take a dominant position in Kurdish politics.

The two parties, who fought a civil war in the 1990s but more recently have taken to sharing power, have just come out of a grueling political battle in Baghdad, where they competed for the presidency of federal Iraq. The PUK came out on top with the election of Barham Salih.

The largest Kurdish opposition party, Gorran, or Movement for Change, was in a distant third with 164,336 votes. There are 111 seats in the Iraqi Kurdistan Parliament, with 11 reserved for minority groups.