Istanbul (AFP) - Hundreds of thousands of people gathered in Istanbul on Sunday for a pro-democracy rally organised by the ruling party, bringing to an end three weeks of demonstrations in support of President Recep Tayyip Erdogan after last month's failed coup.
Followers of Erdogan's Justice and Development Party (AKP) have taken to the streets every night since the attempted putsch on July 15 that claimed at least 273 lives including 34 coup plotters.
The grand "Democracy and Martyrs" rally on Istanbul's Yenikapi square on the shores of the Marmara Sea was due to be held at 1400 GMT under tight security with 15,000 police in charge.
Less than two hours before the start, the square was already a sea of red and white Turkish flags.
Some media predicted that up to 3.5 million people could attend.
Yenikapi is the square often chosen by Erdogan for AKP mass rallies. Prime Minister Binali Yildirim had sent a circular to the party rank and file, saying Sunday's rally would be a "supra-party" gathering and that no partisan slogans would be allowed in a bid to promote unity.
"The spirit of one nation, one flag, one homeland and one state will prevail throughout the rally," he said, warning against any provocation.
A rendition of the national anthem was to open the rally prior to readings from the Koran, Anadolu reported, and a large section of VIP seats were reserved for families of those killed in the coup attempt.
- Opposition leaders to attend -
On the unity theme, Erdogan invited opposition leaders to address the crowds, except from the pro-Kurdish HDP party.
The leader of the opposition National Movement Party (MHP), said on Twitter he had accepted the Turkish president's invitation to take part.
"I will stand on the side of Turkey against traitors and centres of hostility," he wrote in a tweet, retweeted by Erdogan.
Kemal Kilicdaroglu, head of the secular Republican People's Party (CHP), who had initially refused to join the rally, has decided to attend after all because of "our commitment to democracy, our faith in the rule of law and our eternal respect for martyrs".
An AKP follower, who did not wish to be named, expressed his pleasure at the opposition's response. "I support the AKP but I am delighted that the MHP and CHP are supporting this huge rally."
Speaking to Turkish media on Saturday, Erdogan had thanked opposition leaders for agreeing to take part in the rally which he said would "embolden our unity".
"Those who believe in democracy cannot be discouraged by tanks or cannons," he added.
The CHP hosted a mass pro-democracy rally last month on Istanbul's Taksim Square which AKP supporters also attended in a show of patriotic post-coup unity.
- Giant screen in Pennyslvania -
Turkey has accused reclusive US-based cleric Fethullah Gulen of masterminding the coup attempt which was led by a rogue faction in the military.
Erdogan has retaliated with a sweeping crackdown on alleged coup plotters.
Over 60,000 people from the military, judiciary, civil service and education have been dismissed, detained or put under investigation for suspected links to the Gulen movement.
From his base in the US state of Pennsylvania, Gulen has denied the charges.
The mass purge has strained Turkey's ties with its Western allies and cast a shadow over its long-term bid to join the European Union after Erdogan suggested the death penalty might be reintroduced.
Erdogan, who arrived in Istanbul late on Friday, said the rally in Yenikapi would be broadcast live via giant screens nationwide with one also due to be installed in Pennsylvania.
"A mega board will be put up in one more place. Do you know where?" he asked a crowd.
"In Pennsylvania. The message will be delivered," he said.