ISTANBUL -- Turkey's president addressed tens of thousands of people Saturday at a ceremony marking the first anniversary of the country's crushed military coup, vowing to "rip the heads off" of terror groups and of the coup-plotters who tried to end his more than a decade-long rule.

Recep Tayyip Erdogan joined the large, flag-waving crowd who took part in a national unity march in Istanbul, converging at the iconic July 15 Martyrs' Bridge to remember 250 people who died on July 15, 2016 trying to resist the coup. Accompanied by his family and the families of the deceased, he inaugurated a hollow, globe-shaped monument featuring the names of the victims near the foot of the bridge.

"Exactly a year ago today, around this hour, a treacherous attempt took place," Erdogan said.

People listen to the speech of Turkey's President Tayyip Erdogan during a ceremony marking the first anniversary of the attempted coup at the Bosphorus Bridge in Istanbul, Turkey, July 15, 2017. Reuters / Osman Orsal

"The July 15 coup attempt is not the first attack against our country, and it won't be the last," he said, referring to a series of terror attacks that also hit the country. "For that reason, we'll first cut the heads off of these traitors."

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The bridge was the scene of clashes between civilians and soldiers in tanks. At least 30 people died there and more than 2,000 were injured across Turkey in the struggle. Thirty-five coup plotters were also killed.

Photographs of the 250 "martyrs" were displayed on monitors and their names announced. Erdogan praised their bravery saying they were armed only with Turkish flags and "their faith" while resisting coup-plotters in their tanks.

Erdogan was later due to return to Ankara to address parliament at the exact moment it was bombed a year ago. He is also scheduled to inaugurate another monument honoring the dead.

People gather for a ceremony marking the first anniversary of the attempted coup at the Bosphorus Bridge in Istanbul, Turkey on July 15, 2017. Yasin Bulbul/Presidential Palace/Handout via

Turkish soldiers attempted to overthrow the government and the president using tanks, warplanes and helicopters on July 15, 2016. The coup plotters declared their seizure of power on the state broadcaster, bombed the country's parliament and other key locations, and raided an Aegean resort where Erdogan had been on vacation. But Erdogan had already left and the coup attempt was put down by civilians and security forces.

Turkey blames U.S.-based cleric Fethullah Gulen for orchestrating the coup and infiltrating state institutions. Gulen denies the allegations.

In the aftermath of the coup attempt, Turkey declared a state of emergency that has been in place ever since, which has allowed the government to rule by decree and to dismiss tens of thousands of people from their jobs. More than 50,000 people have also been arrested for alleged links to Gulen and other groups.

In the latest government decree published Friday evening, 7,395 more state employees were fired, including teachers, academics, military and police officers, bringing the number of dismissed to more than 110,000. The government calls the crackdown necessary to purge state institutions of those linked to Gulen, but critics say the dismissals are arbitrary and the victims' paths to recourse severely curtailed.

"It has been exactly one year since Turkey's darkest and longest night was transformed into a bright day, since an enemy occupation turned into the people's legend," Prime Minister Binali Yildirim said earlier in the day at a special parliamentary session in Ankara, the capital, attended by Erdogan.

The U.S. State Department on Saturday issued a statement praising the bravery of the Turkish people who took to the streets to "preserve the rights and freedoms of their democratic society."

"The preservation of democracy requires perseverance, tolerance, dissent and safeguards for fundamental freedoms," the agency said, warning that curbs on those key freedoms erode "the foundations of democratic society."

"More voices, not fewer, are necessary in challenging times," the statement said.

NATO Secretary General Jens Stoltenberg paid homage to those who lost lives resisting the coup and said attempts to undermine democracy in any one of the allied nations was "unacceptable."

July 15 has been declared a national holiday in Turkey.

As they did on the night of the 2016 coup attempt, mosques across Turkey after midnight began to simultaneously recite a verse, usually read before Friday prayers, to alert and invite Muslims to the streets.