An attacker armed with a knife killed three people at a church Thursday in the Mediterranean city of Nice, French authorities said, prompting the prime minister to announce that France was raising its security alert status to the highest level.
It was the third attack in two months in France amid a growing furor in the Muslim world over caricatures of the Prophet Muhammad that were re-published by the satirical newspaper Charlie Hebdo.
Other confrontations and attacks were reported Thursday in the southern French city of Avignon and in the Saudi city of Jiddah, but it was not immediately clear if they were linked to the attack in Nice.
Thursday's assailant in Nice was wounded by police and hospitalized after the killings at the Notre Dame Basilica, less than a kilometer (half-mile) from the site in 2016 where another attacker plowed a truck into a Bastille Day crowd, killing dozens of people.
France's anti-terrorism prosecutor's office opened an investigation into the Nice killings, which marked the third attack since the September opening of the trial of 14 people linked to the January 2015 killings at Charlie Hebdo and a kosher supermarket by gunmen who claimed allegiance to the Islamic State group and al-Qaida.
Thursday's attacker was believed to be acting alone and police are not searching for other assailants, said two police officials, who were not authorized to be publicly named.
``He cried `Allah Akbar!' over and over, even after he was injured,'' said Nice Mayor Christian Estrosi, who told BFM television that two women and a man had died, two inside the church and a third who fled to a nearby bar but was mortally wounded. ``The meaning of his gesture left no doubt.''
French media showed the Nice neighborhood locked down and surrounded by police and emergency vehicles. Sounds of explosions could be heard as sappers exploded suspicious objects.
The lower house of parliament suspended a debate on France's new virus restrictions and held a moment of silence Thursday for the victims. Prime Minister Jean Castex rushed from the hall to a crisis center overseeing the aftermath of the Nice attack and later returned to announce the alert level increase. French President Emmanuel Macron was headed to Nice later in the day.
In Avignon on Thursday morning, an armed man was shot to death by police after he refused to drop his weapon and a flash-ball shot failed to stop him, one police official said. And a Saudi state-run news agency said a man stabbed a guard at the French consulate in Jiddah, wounding the guard before he was arrested.
Islamic State extremists had issued a video on Wednesday renewing calls for attacks against France.
Many groups and nations, however, issued their condolences Thursday, standing firmly with France.
The French Council of the Muslim Faith condemned the Nice attack and called on French Muslims to refrain from festivities this week marking the birth of Muhammad ``as a sign of mourning and in solidarity with the victims and their loved ones.''
Turkey's Foreign Ministry strongly condemned the attack in Nice. ``We stand in solidarity with the people of France against terror and violence,'' the statement said.
Relations between Turkey and France hit a new low after Turkey's president on Saturday accused Macron of Islamophobia over the caricatures and questioned his mental health, prompting Paris to recall its ambassador to Turkey for consultations.
The attack in Nice came less than two weeks after another assailant beheaded a French middle school teacher who showed the caricatures of the Prophet Muhammad for a class on free speech. Those caricatures were published by Charlie Hebdo and cited by the men who gunned down the newspaper's editorial meeting in 2015.
In September, a man who had sought asylum in France attacked bystanders outside Charlie Hebdo's former offices with a butcher knife.