It was the worst attack in years on the event in Jerusalem, a city where the religious population is more prominent than in other parts of Israel.
“I saw an ultra-Orthodox youth stabbing everyone in his way,” said Shai Aviyor, a witness interviewed on Israel’s Channel 2 television.
“We heard people screaming, everyone ran for cover, and there were bloodied people on the ground,” Aviyor said.
A paramedic with the Magen David Adom rescue service said at least six people had been injured, and at least two appeared to be in serious condition.
Police spokeswoman Luba Samri said a suspected ultra-Orthodox Jewish man had stabbed at least four of the marchers.
The march, which attracts thousands of participants, has long been a focus of tension between Israel’s predominantly secular majority and the ultra-Orthodox Jewish minority, who object to public displays of homosexuality.
Oded Fried, the head of a leading gay rights group, said the march would go on despite the attack. “Our struggle for equality only intensifies in the face of such events,” he said.