
An Algerian student claiming to be an ISIS soldier shouted 'this is for Syria' as he attacked a police officer outside Paris's Notre Dame Cathedral on Tuesday afternoon.

The man, whose name has not been released but is said to be a mature student in his 40s, was shot and injured by police after he used a hammer to attack an officer patrolling with two other policemen at 4.30pm local time.

One of the officers responded with two gunshots, which injured the assailant, who was carrying kitchen knives, a hammer and other unsophisticated weapons.

Paris prosecutors opened a counter-terrorism investigation soon after the attack after the hammer-wielding Algerian said he was an 'ISIS soldier of caliphate', according to a probe source.

French Interior Minister Gerard Collomb says the attacker cried 'it's for Syria' as he went after officers patrolling an esplanade in front of the famous landmark which was put on lockdown and is tonight being guarded by soldiers.

A man was shot by police after he attacked an officer with a hammer outside Paris's Notre Dame Cathedral

The man, who has not been identified, is believed to have attacked an officer who was patrolling with two other policemen at about 4.30pm local time

The officer responded with two gunshots, which injured the assailant and dozens of other officers were quick to respond to the incident

At least one person on the scene said on Twitter that he was inside the church and could hear sirens outside. He later said that officials were not letting anyone in or out of the cathedral

About 900 people inside the church were told to sit down and put their hands up as police investigated the attack

Police officers and soldiers seal off the access to Notre Dame cathedral after a man attacked officers with a hammer while patrolling the esplanade in front of the famous landmark, in Paris, France

The officer responded with two gunshots, which injured the assailant, who was carrying kitchen knives, a hammer and other unsophisticated weapons. Paris prosecutors opened a counterterrorism investigation soon after the attack

French police lined the streets outside Notre Dame Cathedral as officials investigated the attack

After the attacker was shot, he is said to have claimed to be a soldier of Islamic State.

Just yesterday ISIS released a statement said to be from what it called its Commander of The Believers in France to the crossed (Christians) French people.

It read: 'O' people of France, demand of your government to stop its campaign against the Islamic State, if not, we will conduct operations of invasion and horror as you have lived in the cities of Paris and Nice.

'May peace be upon those who follow the guided message.

'Soldiers of the Islamic State in France.'

Collomb told reporters near the cathedral in central Paris: 'A man came behind these police officers and, armed with a hammer, started hitting one of them. His colleagues reacted with composure...and fired,'

The minister said the man 'was in hospital,' but had no further details of his condition, adding that the injured attacker seemed to have acted alone.

A soldier patrols on a bridge with the Notre Dame in the background (far left) as two men walk by in the aftermath of the attack

Forensic experts and police officers investigate the crime scene after a man attacked officers with a hammer on the esplanade of the Notre Dame cathedral in Paris, France

A forensic tent is erected as experts prepare to analyse the scene of the crime involving a suspected ISIS terrorist

Police union official Cedric Michel said the man armed with a hammer went after the police officer who was patrolling on the esplanade in front of Notre Dame Cathedral and officers shot at him after he refused to stop threatening them with the hammer.

One officer was lightly injured and the assailant was shot in the chest, according to one source.

Footage seen on social media showed the assailant lying on the ground after being shot.

Police had earlier said they were dealing with an incident in the courtyard outside the world-famous tourist site amid reports of panic and gunshots in the area.

Officials warned people to stay away from the area after saying there was an 'incident' at the popular tourist destination which was locked down with 900 people inside.

Former US ambassador to the United Nations Nancy Soderberg was among the hundreds of people held inside the cathedral.

She was admiring the church's stained glass windows on Tuesday when she heard an announcement in French urging visitors to stay calm as police dealt with an incident outside.

Soderberg said those inside got nervous when they were told soon after that the cathedral's doors were closing and everyone had to stay there.

She says the group stayed calm and orderly throughout despite not knowing what was happening, though 'everyone was very quiet and very scared' when police came in to check the cathedral's pews row by row.

Soderberg tweeted a photo from inside the Notre Dame showing those locked inside putting their arms in the air as instructed by police.

Authorities told people to stay away from the area and some took refuge inside the cathedral. People inside Notre Dame, the nearby Sainte-Chappelle cathedral and area bars and cafes were told to stay inside while the police operation was underway.

Police had earlier said they were dealing with an incident in the courtyard outside the world-famous tourist site amid reports of panic and gunshots in the area

French police officials gather at the entrance to Notre-Dame Cathedral in Paris on Tuesday afternoon

Police officers in helmets and vests who were carrying guns surrounded the area on Tuesday

Paris police say an unidentified assailant has attacked a police officer near the Notre Dame Cathedral, and the officer then shot and wounded the attacker

French police stand at the scene of a shooting incident near the Notre Dame Cathedral in Paris

'So we are trapped in Notre Dame Cathedral,' Matthew CurrieHolmes, a tourist from Los Angeles, wrote on Twitter. 'Something is happening outside we don't know what it is. Police sirens can be heard.'

CurrieHolmes, who was also in London during the terror attack on Saturday, later said everyone was safe but that officials were not letting anyone in or out of the cathedral.

About 900 people inside the church were told to sit down and put their hands up as police investigated the attack.

Photos on social media show rows of dozens of people sitting in wooden chairs with their arms up.

By 5.30pm local time, an hour after the attack, CurrieHolmes said that he and other visitors were being let out of the cathedral.

'They started to let everyone out! Everyone is save,' CurrieHolmes wrote on Twitter. 'Please do not disseminate false information.'

The police department tweeted about the operation on Tuesday afternoon but did not provide any details. A police official would not provide further information.

Officials carrying police dogs arrived at the scene shortly after 4.30pm local time on Tuesday

An hour after the attacks, police allowed those who were trapped in the church to leave

Witnesses around Notre Dame Cathedral have described the dramatic police operation in the tourist-filled site in central Paris

Officials wearing full gear stood under a closed souvenir shop near the Notre Dame Cathedral

Officials warned people to stay away from the area after saying there was an 'incident' at the popular tourist destination, after a hammer-wielding man was shot by a police officer

Police arrived at the cathedral amid reports of gunshots and panic. Many people were stuck inside the cathedral at the time

Large numbers of police cars filled the area on the Ile de Cite island in the River Seine in the center of Paris.

Witnesses around Notre Dame Cathedral have described the dramatic police operation in the tourist-filled site in central Paris.

Lawrence Langner, a 73-year-old American visiting the neighborhood just across the Seine River from the cathedral, told The Associated Press that he suddenly heard a commotion and two detonations like gunshots.

Journalist David Metreau, who said his office overlooks the square, tweeted that there were two blasts that sounded like shots, and posted a photo of a body lying seemingly inert on the ground.

Others posted photos online of what appeared to be the interior of medieval Notre Dame, one of France's most-visited monuments.

France remains on high alert after a series of deadly terror attacks in recent years.

In April, traffic officer Xavier Jugele was shot dead while on duty on the Champs Elysees just days before the French presidential election.

The police department tweeted about the operation on Tuesday afternoon but did not provide any details. A police official would not provide further information

Large numbers of police cars filled the area on the Ile de Cite island in the River Seine in the center of Paris

France remains on high alert after a series of deadly terror attacks in recent years, including one in April

ISIS claimed the killing by 39-year-old Karim Cheurfi, who was shot dead by police in a gun battle. Two other officers were injured in the attack.

A month earlier a convicted criminal with links to radical Islam shouted 'I am here to die for Allah, there will be deaths' seconds before he was shot dead during an attack at Paris Orly airport.

The 39-year-old, named locally as career criminal Ziyed Ben Belgacem, was killed after wrestling a soldier's gun from her and fleeing into a McDonald's. He sent a text message to his brother and father stating 'I shot the police', shortly before he was killed.

It followed the shooting in February of a man outside the Louvre museum in the heart of Paris after he attempted to storm the historic art gallery.

On July 14 last year amid Bastille Day celebrations in the Riviera city of Nice, a large truck was driven into a festive crowd killing 86 people. The driver was shot dead. ISIS extremists claimed responsibility for the attack.

Just 12 days later two ISIS fanatics stormed into a church in Normandy and slit the throat of a priest as he was celebrating mass.

Police union official Cedric Michel said the man armed with a hammer went after the police officer who was patrolling on the esplanade in front of Notre Dame Cathedral

Police sources said the officers shot at the man after he refused to stop threatening them with the hammer

Police boats were patrolling the river near the Notre Dame Cathedral after the incident on Tuesday

Paris's Notre Dame Cathedral is a tourist hotspot in the French city, with visitors travelling from all over to see the structure

A month earlier, two French police officers were murdered in their Paris home in front of their three-year-old son.

Again ISIS claimed responsibility for the slaying, which was carried out by a jihadist with a prior terrorist conviction. He was killed by police on the scene.

The killings came after a massacre in the French capital in November 2015 in which ISIS militants went on the rampage murdering 130 people.

They used machine guns to slaughter revellers at the Bataclan music hall and in bars and restaurants in some of the city's most popular night spots. A suicide bomber also targeted to Stade de France stadium.

The atrocity led to the declaration of a state of emergency in France.

In January the same year, two brothers killed 11 people inside the Paris building where the satirical magazine Charlie Hebdo is headquartered in what ISIS claimed was retaliation for the publication of cartoons about the Prophet Muhammad.

More were killed subsequently in attacks on a kosher market in eastern Paris and on police. There were 17 victims in all, including two police officers. The attackers are killed.