Two bystanders who were seriously injured in a knife attack at Amsterdam's Central Station are US citizens, the US ambassador said.
"We are aware that both victims were US citizens and have been in touch with them and their families," Pete Hoekstra said.
Police shot and wounded a 19-year-old Afghan man with a German residency permit. He stabbed the two people at the Dutch capital's busy station in the city centre yesterday.
"We are seriously taking into account that there was a terrorist motive," Amsterdam police spokesman Frans Zuiderhoek told AFP.
Earlier witnesses described scenes of panic as gunshots rang out and thousands of commuters and tourists were evacuated from the rail terminus.
"A man in the west side tunnel of Amsterdam Central Station stabbed two other people and directly after that he was shot by the police," another police spokesman Rob van der Veen said, adding terrorism was not being ruled out by investigators.
"The two people are very badly injured, and they were brought to the hospital," he said.
"We are looking at all scenarios, also the worst scenario, which is terrorism."
One witness said he saw a young man "stumble" into his flower shop at the station with a bleeding wound to his hand.
"Shortly afterwards I heard some shots and I know something has gone badly wrong," Richard Snelders told the ANP news agency. A while later he saw another man lying on the ground nearby, he said.
"The first thing that comes up in your mind is that it's a terror attack. After all, you are at Amsterdam Central Station. There was a lot of panic," Snelders said.
Police quickly arrived at the scene with video images showing police ordering the suspect in English to "stay down" after he had been shot.
Images posted on social media showed security guards ushering passengers towards exits and paramedics arriving at the scene with stretchers.
Police spokesman Zuiderhoek said the knifeman's condition was not life-threatening, but that he had been shot in the lower body.
"At this moment he is under police custody in hospital. He is being questioned about his motive," Zuiderhoek added.
Dutch police were also in close contact with their German counterparts in regards to the suspect's background, he added.
Two platforms at the station - located in the Dutch capital's historic canal-ringed city centre - had been evacuated and closed off to passengers, police said, and were reopened for rail traffic two hours later.
A special police department opened a routine probe into why police shot the man.
The Netherlands has so far been spared from the slew of terror attacks which have rocked its closest European neighbours in the past few years.
But amid a number of scares and reports that people linked to some of those attacks may have crossed briefly into the country, top Dutch security and intelligence officials have stressed that the threat level is substantial.
Police declined to speculate on the reasons for the incident, but the Afghan Taliban in a statement on Friday called for attacks on Dutch troops following plans by Dutch far-right politician Geert Wilders to stage a Prophet Muhammad cartoon competition in the Dutch Parliament.
Wilders, who received several death threats has since cancelled the competition which has angered Muslims and sparked protests, saying he wanted to "avoid the risk of making people victims of Islamist violence".
Around 250,000 people travel through Central Station every day, according to statistics provided by the Amsterdam.info travel guide.