Dutch police have named a suspect in the 'terrorist motivated' shooting on a tram in Utrecht, which resulted in the death of at least one person and left several others injured, as a 37-year-old Turkish-born man.
Police tweeted a photograph of Gökmen Tanis, believed to have been captured on the tram's CCTV just minutes before the incident at 10.45am this morning, and urged the public to 'look out for him but do not approach.'
The gunman, who may not have been acting alone, fled the scene, reportedly in a red Renault Clio compact sedan, which has since been found abandoned in Utrecht.
The photograph was released as heavily armed police gathered in front of an apartment block some 200 yards from the scene the shooting, where the suspected gunman is believed to be holed up. Police said they were searching for the shooter 'with all possible means.'
Shortly after 12.30pm local time, the Dutch government raised the terrorism threat level to the highest possible in the province of Utrecht, and local residents in one of the Netherlands' biggest cities have been urged to stay indoors in case of further incidents.
The head of the Dutch counter-terrorism agency Pieter-Jaap Aalbersberg said in a statement that the 'threat level has gone to 5, exclusively for the Utrecht province,' referring to the highest level, adding that the shooting 'appears to be a terrorist attack'.
'The culprit is still on the run. A terror motive cannot be excluded,' he said in a Twitter message. He called on citizens to closely follow the indications of the local police.
Utrecht University has put the entire campus on lockdown, and according to Dutch news website NOS News, all train traffic to Utrecht Central has stopped.
Police have also instructed all schools, as well as mosques and transportation hubs, in the city to keep their doors closed, while the manhunt continues.
Dutch military police have been ordered to be on 'extra alert' at Dutch airports and 'vital buildings' due to the ongoing police manhunt.
Police spokesman Bernhard Jens said no one had been detained yet in the shooting, and one possible 'explanation is that the person fled by car.'
He did not rule out the possibility that more than one shooter was involved in the attack.
'We want to try to catch the person responsible as soon as possible,' Jens said.
The first casualty was reported by the Dutch ANP news agency, which stated that the victim was completely covered with a sheet and lying on the tracks between two carriages.
One witness told NOS News they had seen an injured person running out of the tram with blood on her hands and clothes who then fell to the ground.
'I brought her into my car and helped her. When the police arrived, she was unconscious,' the witness, who was not named, told the broadcaster.
Local resident Jimmy De Koster also witnessed the incident and told De Telegraaf: 'I was standing at the traffic lights on 24 Oktoberplein and I saw a woman lying down, I think she would have been between 20 and 35 years old.
'She shouted 'I didn't do anything'.'
The Utrecht police said a square at a tram station outside the city centre had been cordoned off as emergency services attend the scene.
Officials added that trauma helicopters were sent to the incident at 24 Oktoberplein, and they are appealing to the public to stay away to allow first responders to do their work.
They had no further details about the incident and could not say how badly hurt the victims were, or how many had been injured.
'Several shots were fired in a tram and several people were injured. Helicopters are at the scene and no arrests have been made,' said police spokesman Joost Lanshage.
Dutch Prime Minister Mark Rutte called the situation 'very worrying' and the country's counterterror coordinator said in a tweet that a crisis team was meeting to discuss the situation.
Utrecht is located about 25 miles south of Amsterdam in central Holland.
Dutch military police have been put on extra alert at Dutch airports and at key buildings across the country, including in Amsterdam and The Hague, as the Utrecht manhunt is taking place.
German police say they have upped surveillance on the country's border with the Netherlands and are on the lookout for the gunman believed to be responsible for the Utrecht shooting.
Heinrich Onstein, a spokesman for the federal police in the border state of North Rhine-Westphalia, said additional police had been added to watch not only major highways, but also minor crossings as well as railway routes.
He says the federal police are in close contact with authorities in the Netherlands and have a description of the suspect.
British Foreign Secretary Jeremy Hunt tweeted his concern in the wake of the incident, saying the UK 'stands with the people of the Netherlands'.
'Hugely concerning news of a gunman opening fire on a tram in Utrecht, no doubt with innocent people just getting on with their day,' Mr Hunt wrote.
'We are in contact with Dutch authorities, urgently seeking further information. The UK stands with the people of the Netherlands '
All major political parties including Rutte's VVD announced that they were suspending campaigning ahead of Wednesday's local elections which will determine the make-up of the Dutch senate.
The Netherlands has been largely spared the kind of attacks which have rocked its closest European neighbours in the past few years, but there has been a series of recent scares.
In August, a 19-year-old Afghan with a German residence permit stabbed and injured two American tourists at Amsterdam's busy Central Station before being shot and wounded.
In September, Dutch investigators said they had arrested seven people and foiled a 'major attack' on civilians at a major event in the Netherlands.
They said they had found a large quantity of bomb-making materials including fertiliser likely to be used in a car bomb. The men were arrested in the cities of Arnhem and Weert.
In June, two terror suspects were arrested while close to carrying out attacks including at an iconic bridge in Rotterdam and in France, prosecutors said.
The men aged 22 and 28, who were of Moroccan origin, made a film at the Erasmus bridge in which they sang a martyrdom song, they said.