ISTANBUL — Turkey’s ruling party won a third term in parliamentary elections Sunday, setting the stage for the rising regional power to pursue trademark economic growth, assertive diplomacy and an overhaul of the military-era constitution.
However, results indicated that the Justice and Development Party of Prime Minister Recep Tayyip Erdogan failed to win a two-thirds majority in parliament, a shortcoming that would force it to seek support for constitutional change from other political groups.
With 99 percent of ballots counted, Mr. Erdogan’s party had 50 percent of the votes, according to TRT, the state-run television. It said the Republican People’s Party, the main opposition group, won 26 percent of the vote.
TRT said another opposition party, the Nationalist Action Party, had 13 percent of the vote, signaling that it would stay in parliament by crossing a 10 percent vote threshold designed to keep out smaller parties.
According to the tally, the ruling party won 326 seats in the 550-seat parliament, a comfortable majority that would ensure the continuation of its single-party rule. It had 331 seats in the outgoing parliament. Lawmakers serve four-year terms.
Several thousand supporters gathered Sunday night outside the ruling party headquarters in Ankara, chanting pro-government slogans and waving Turkish flags as Mr. Erdogan emerged to deliver a victory speech from the balcony.
The prime minister alluded to the climate of impunity and political chaos that prevailed in past decades in Turkey, which endured several military coups but made strides in democratic development as part of its bid to join the European Union.
Despite Turkey’s achievements during his tenure, he is viewed with skepticism by the opposition and some commentators who note hints of an autocratic leadership style.
“We will be humble. We have never displayed pride or boasted,” Mr. Erdogan said in an apparent attempt to counter the criticism. He pledged to start work on enacting a new constitution.
“We will be seeking consensus with the main opposition, the opposition, parties outside of parliament, the media, NGOs, with academics, with anyone who has something to say,” he said.
About 50 million Turks, or two-thirds of the population, were eligible to vote. NTV television said turnout was 84.5 percent.
For the first time, voters cast ballots in transparent plastic boxes in which the yellow envelopes could be seen piling up. The measure was designed to prevent any allegations of fraud. In past elections, wooden boxes were used.
The Anatolia news agency reported that police detained 34 people in the southeast province of Batman who were suspected of trying to coerce people into voting for the Peace and Democracy Party, a Kurdish party accused by officials of links to Kurdish rebels.