By Noemie Olive

SAINT-ETIENNE-DU-ROUVRAY, France (Reuters) – Knife-wielding attackers interrupted a church service in France, forced the priest to his knees and slit his throat on Tuesday, an attack that President Francois Hollande said showed the threat from Islamist militancy was greater than ever.

Police shot and killed the attackers as they emerged from the church, freeing three hostages, one of whom was seriously wounded.

The knifemen arrived during morning mass in Saint-Etienne-du-Rouvray, near Rouen, northwest of Paris, where the 85-year-old parish priest Father Jacques Hamel was leading prayers.

“They forced him to his knees and he tried to defend himself and that’s when the drama began,” Sister Danielle, who escaped as the attackers slayed the priest, told RMC radio.

“They filmed themselves. It was like a sermon in Arabic around the altar,” the nun said.

Speaking at the scene, Hollande called it a “dreadful terrorist attack,” adding that the attackers had pledged allegiance to Islamic State, the militant group that he said had declared war on France.

News agency Amaq, which is affiliated with Islamic State, said two of its “soldiers” had carried out the attack. Police said one person had been arrested.

Tuesday’s attack came less than two weeks after a Tunisian plowed a truck into a crowd in the French Riviera city of Nice, killing 84 people. Islamic State claimed that attack.

France is a major partner in the U.S.-led military coalition bombing Islamic State targets in Iraq and Syria. The White House condemned Tuesday’s attack and commended the French police’s “quick and decisive response.”

Several French media reported that one of the assailants was a local who had spent a year in jail on his return from Turkey after being intercepted trying to travel to Syria, but had been freed on bail with an electronic tag pending trial for terrorism offences.

The prosecutor’s office said the identification of the two suspects was still under way.

MERCILESS

A horrified local resident, Cecile Lefebre, said: “I have no words. How do you arrive at this point, killing people in cold blood like this? It’s pure barbarity.”

Since the Bastille Day mass murder in Nice, there has been a spate of attacks in Germany, some of which appear to be Islamist-inspired.

“In the face of this threat that has never been greater in France and Europe, the government is absolutely determined (to defeat) terrorism,” Hollande said in a televised address.

But former president Nicolas Sarkozy, who is expected to enter a conservative primary for next year’s presidential election, accused the Socialist government of being soft.

“We must be merciless,” Sarkozy said in a statement to reporters. “The legal quibbling, precautions and pretexts for insufficient action are not acceptable. I demand that the government implement without delay the proposals we presented months ago. There is no more time to be wasted.”

The center-right opposition wants all Islamist suspects to be either held in detention or electronically tagged to avert potential attacks.

Far-right National Front leader Marine Le Pen, who is also expected to run for the presidency, said both Sarkozy’s and Hollande’s parties had failed on security.

“All those who have governed us for 30 years bear an immense responsibility. It’s revolting to watch them bickering!” she tweeted.

Hollande said France should “use all its means” within the law to fight Islamic State.

Pope Francis condemned what he called a “barbarous killing”.

“The fact that this episode took place in a church, killing a priest, a minister of the Lord and involving the faithful, is something that affects us profoundly,” Vatican spokesman Father Federico Lombardi said.

In a telephone call with the pope, Hollande expressed “the sorrow of all French people after the heinous murder of Father Jacques Hamel by two terrorists,” and said everything would be done to protect places of worship, the presidential palace said.

Jean-Pierre Raffarin, a former conservative prime minister who now heads the Senate’s foreign affairs committee tweeted: “Everything is being done to trigger a war of religions.”

(Additional reporting by Chine Labbe, Marine Pennetier, Michel Rose and Richard Lough in Paris and Jess Mason in Washington; Writing by Richard Lough and Paul Taylor; Editing by Jeremy Gaunt and Robin Pomeroy)