Some 15 parties and 200 independent candidates were contesting 550 seats for four-year terms in parliament, with surveys in past weeks indicating the Justice and Development Party of Prime Minister Recep Tayyip Erdogan was headed for another win.
About 50 million Turks, or two-thirds of the population, were eligible to vote. The last polls were scheduled to close at 5 p.m. (1400GMT) in western Turkey. Reporting results was barred until 9 p.m. (1800GMT), although preliminary returns have emerged earlier in the evening in past elections.
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.
"We have spoken, and now it is time for the people to speak," Erdogan said in Istanbul. "For us, this will be the most honorable decision and one that we will have to respect. As far as I know, the election process is continuing through the country without any problems."
A group of supporters greeted his arrival at a polling station by shouting: "Turkey is proud of you."
The Anatolia news agency reported later that police detained 34 people in the southeast province of Batman for allegedly trying to coerce people into voting for the Peace and Democracy Party, a Kurdish party accused by officials of links to Kurdish rebels.
The party is fielding independent candidates in order to work around requirements for a 10 percent vote threshold that keeps smaller parties out of Turkey's parliament. It seeks more rights and autonomy in the southeastern strongholds of the ethnic minority, which makes up about 20 percent of Turkey's 74 million people.
Turkey, a NATO ally with a mostly Muslim population, stands out in a region buffeted by popular uprisings as a rising power with traditional Western alliances as well as growing ties in the east and elsewhere. In the past decade, the government has sharply reduced the political clout of the military, and taken some steps to ease restrictions on minorities, though reforms have slowed in recent years.
Despite its successes, Turkey's government faces opposition accusations that it seeks to consolidate power at the expense of consensus-building. Much of the debate among commentators has centered on whether the ruling party can secure a two-thirds majority in parliament that would enable it to push through a new constitution without the support of other political groups.
Erdogan has promised that a new constitution would include "basic rights and freedoms," replacing a constitution implemented under the tutelage of the military in 1982. However, he has provided relatively few details on a possible new draft.
The government has Islamic roots, long a source of suspicion among secular circles that once dominated Turkey and fear that Erdogan seeks to impose religion on society.
Turkey's leaders, however, describe themselves as moderates and "conservative democrats" who are committed to the ideals of Western-style democracy. After winning election in 2002, they implemented economic reforms that pulled the country out of crisis. The growth rate last year was nearly 9 percent, the second highest among G-20 nations after China.
Still, political reforms faltered in the ruling party's second term. Turkey's bid to join the European Union has stalled, partly because of opposition in key EU nations such as Germany and France. Critics point to concerns about press freedom and the Turkish government's plans for Internet filters as signs of intolerance toward views that don't conform to those of Turkey's leadership.
Four people were detained Sunday in the southeast province of Sanliurfa for allegedly voting more than once with other people's ballot papers. In the capital, Ankara, police fired in the air and used pepper spray to break up scuffles at a polling station where a group of voters wrongly accused another group of having fake ballot papers, the Anatolia agency said.
But for all of Turkey's challenges, Sunday's vote was an indicator of stability in a country that suffered fractious coalition politics and military coups in past decades. Most voting was peaceful and orderly, with large crowds gathering early to cast ballots.
"We have come to the end of a long marathon," Kemal Kilicdaroglu, head of the opposition Republican People's Party, said after arriving at a polling station with his wife and son. "Today is the time for a decision by the people. We will respect their decision. There is a good mood. There is a democracy feast."
--- Associated Press reporter Gulden Alp contributed from Ankara, Turkey.
