At least nine people were killed and dozens injured when a truck plowed through a crowd at a popular Christmas market in Berlin late Monday, police said.

Polizei Berlin confirmed the deaths on Twitter, adding later that a suspect had been arrested near the scene. A passenger in the truck died, although it’s not clear how or when that happened yet. The identity of the passenger and arrested suspect have not been released. Police spokesman Winfried Wenzel told ZDF television that the suspect arrested was believed to be the truck driver.

Officials said there is no further immediate danger from the attackers.

The attack happened in Breitscheidplatz, a major square in the center of the German capital. 

A large Scania truck with its windshield smashed out could be seen on the sidewalk alongside the market, although officials have not yet confirmed that it was the truck used in the attack.  

German police haven’t announced a motive in the attack. However, CBS News correspondent Charlie D’Agata reports witnesses saying that there was no doubt it was a deliberate attack based on the way it jumped the curb.

Witness Shandana A. Durrani said she was walking and texting when the truck entered the market about 20 feet away. She said she heard some popping but wasn’t sure if it was a gun or not.

“If I hadn’t stopped to check my phone, I would have been hit,” Durrani said. “Everyone went scurrying. So many people hurt.”

She said the way the market was laid out, “there was just no place to run so a lot of us hid behind other stalls.”

Every year, the city of Berlin hosts a Christmas market there near the fashionable Kurfuerstendamm avenue. The attack happened at the foot of the landmark Kaiser Wilhelm memorial church, which was kept as a ruin after World War II.

However, several people in the U.S. intelligence community told CBS News that the situation in Berlin has all the hallmarks of a terror attack.

Officials here in the U.S. say it bears similarities to the recent terror attack in Nice, France - in which 86 people were killed and hundreds injured - and is what terror groups have been calling for their followers to do.

German police have recently rounded up a series of people for planning attacks on Christmas markets, and even detained last week a 12-year-old Iraqi boy for attempting to set off a nail bomb in one of them.

CBS News correspondent Margaret Brennan reports U.S. State Department issued a warning in late November specifically cautioning Americans in Europe to “exercise caution at holiday festivals, events, and outdoor markets.” The release cited ISIS, al Qaeda and “their affiliates” as planning attacks using “conventional and non-conventional weapons” focusing on the upcoming holiday season and “associated events.”

Many in Germany have been fearful of a rise in terrorism since the country took in more than a million migrants and refugees last year, mostly fleeing conflict in the Mideast. 

German prosecutors were already investigating a 12-year-old boy who allegedly attempted to set off a nail bomb at a Christmas market in the southern city of Ludwigshafen last week.

The German-born son of Iraqi parents is alleged to have tried to set off the device at the Christmas market on Nov. 26, and again outside city hall on Dec. 5, Focus magazine reported, citing security sources.

In the second failed attempt, a passer-by spotted the backpack containing the device and reported it to authorities. Inside they found a glass jar packed with firecrackers with nails taped to it, Focus reported.

Police said it would have burned but would not have exploded.

Stephan Meyer, the parliamentary spokesman on security issues for Chancellor Angela Merkel’s conservative bloc, said the boy apparently had turned rapidly to Islamic extremism.

“This shows how quickly the radicalization of a young person, a child, can take place,” he said.

In the Nice attack, officials said Mohamed Lahouaiyej Bouhlel deliberately drove a 19-ton truck into thick crowds on the French Riviera celebrating the country’s independence day.