Eight people – including four foreign tourists – were stabbed in Jerash, a city in Jordan popular with visitors.
Authorities said the victims included tourists from Mexico and Switzerland. Police sources told the Guardian that three of the stabbed were Mexican and one was Swiss. Two people were taken to the capital Amman for treatment, local media reported.
The 22-year-old was arrested at the scene and is believed to have acted alone, sources said.
The man came from a nearby Palestinian refugee camp, which housed about 35,000 people and used to wash cars at a border station, a friend of his family told the Guardian.
"If he did that, we are all in shock," said the man. “He was a shy, normal guy. If you talked to him, he would set his eyes on the floor.
A group representing the camp residents issued a statement on Wednesday saying they "denounce and condemn the terrorist act committed by one of these cowards in Jerash."
Natalie, a witness to the attack, said she and her tour group were near the Roman city racetrack just before 11:16 am local time when they saw a large group and heard a commotion.
She said they realized there were people bleeding: “It looked like there was a total fight. And then I saw this guy's hand open and I knew someone had stabbed people. "
She said local guides told her and her group that the attack had been carried out by a "psychopath" who had been arrested and that the rest of the place was now safe.
"We walked a little farther toward the columns and there was a machete there," she said. “There were no police lines installed or anything at the scene. People were walking and you could walk right through all the blood.
She said she counted at least four victims and said three of them appear to be seriously injured.
An allegedly recorded video after the stabbing showed a woman lying face down on the floor while others pressed a handkerchief into an apparent back injury.
An alarmed woman was heard asking for help in Spanish, shouting, "There was a stab. They have a knife! Please help him here! Please!"
Another man was sitting nearby, with a bloody leg, and bloodstains covered the ground around him.
There were conflicting reports of injury severity. Local media said at least two people were in critical condition, while Reuters reported that the victims were taken to hospital with minor injuries.
Jerash is home to one of the best preserved Roman cities in the world and is a major attraction for tourists who are a lifeline to the Jordanian economy.
Tourism contributes about 10% of Jordan's GDP. Visitors declined significantly after the outbreak of the civil war in neighboring Syria and the resumption of the Iraq conflict, but have recovered in the last three years.
Sam Jones in Madrid contributed to this report