Istanbul voters split
Schools, where voters have been casting their ballots, were noticeably more crowded by midday in Turkey than in previous elections, MEE correspondent Yusuf Selman Inanc reported.
Experts predict that this election will see one of the highest voter turnouts in Turkey's history.
One school in Istanbul's Fatih district already had 200 people out of 364 registered voters cast their ballot by 1pm local time, an election officer told MEE.
The crowds in Fatih district, a stronghold of the ruling Justice and Development Party (AKP), were distinctly supportive of President Recep Tayyip Erdogan.
"We can't give up Erdogan," said Busra Yavuz.
"We don't believe the [opposition Republican People's Party, or CHP] can help the country flourish. It is Erdogan who will overcome all problems if there are any," she told MEE.
Another Erdogan supporter, Yakup Kizil, said the incumbent president "has to remain in power".
"If Turkey wants to continue challenging the dominance of the West, terrorism and its supporters, Erdogan must win," Kizil told MEE.
"Otherwise, these people [the opposition National Alliance, which includes the CHP] will cause the loss of Turkey's gains in the fields of international relations, economy, technology and others."
In Maltepe district, a CHP stronghold, the atmosphere was starkly different.
"Today, we are marking the start of the spring," said Ayhan Isil, a retired teacher, referring to the CHP's main campaign slogan: "Springs will flourish".
"We are fed up with the current government," Isil told MEE.
"They have dragged the country out of its path, created by [Mustafa Kemal] Ataturk."
Murat Pinar, another voter in the same constituency, shared a similar view.
"The government must go. Otherwise, we will not survive economically," he said.
Polls show that Erdogan and CHP leader Kemal Kilicdaroglu are in a neck-and-neck race, with the possibility of run-off very high.