Two off-duty New York police detectives apprehended a man who stabbed a Russian tourist in the middle of the crowded Hollywood Walk of Fame on Wednesday.

Officer Ricardo Hernandez, a spokesman for the Los Angeles Police Department, said a man, in his 50s, used a large kitchen knife and attacked a tourist who is believed to be in his late 20s. The tourist was doing sightseeing in Hollywood with his family.

The two off-duty detectives, in Los Angeles on police business, saw the attack and intervened likely saving the sightseer’s life, police said.

The wounded tourist was undergoing surgery and was expected to survive, said Cmdr. Andrew Smith, a spokesman for Los Angeles Police.

Smith said the attack was unprovoked.

"This victim was here with his family just walking in the area when this guy jumped out for no reason," he said.

Police were interviewing a slew of witnesses who saw the stabbing take place and collected extensive surveillance footage, police said.

Liza Brown, a 35-year-old social media marketing manager visiting Los Angeles from Chesterfield, South Carolina, said she was shopping at the popular beauty store Sephora when the stabbing happened.

"Everyone started running to the windows. I turned around and the first thing I saw was a guy bent over," Brown said. "He kept looking at his hand and putting it to his neck. There was blood squirting out between his fingers.

"It was like something out of a horror movie," said Brown, who works for a production company and was in Los Angeles for the first time to film a documentary.

Brown said she saw a man in plain clothes holding a gun on the stabbing suspect and then using his foot to keep him on the ground. The man who was stabbed was able to stand, she said.

Brown said Sephora employees locked the business during the attack and that no one could enter or exit the building until police cordoned off the crime scene.

"I was thinking, 'Is this really happening?'" Brown said. "I was shocked. It was like a nightmare."

Smith credited the New York detectives with saving the tourist's life.

"If it were not for the actions of these heroic officers, it's likely that this person would not have survived," Smith said.

The stabbing happened across the street from the famed TCL Chinese Theatre, the site of the Oscars red carpet, countless movie premieres and the Walk of Fame, where celebrities pose for pictures while placing their hands and feet in concrete.

In June 2013, a 23-year-old woman was stabbed to death in the same area after refusing to give panhandlers $1 for taking their photo.

The Associated Press contributed to this report.