The reports said the Palestinian, a resident of the West Bank city of Qalqilya, worked in a factory where the shooting took place.
Israel’s national ambulance service said a man and a woman were wounded critically in the attack in the Barkan industrial area, where thousands of Palestinians work in Israeli-owned businesses, Reuters reported.
Another woman sustained serious injuries and was taken to hospital.
Israeli police and soldiers were searching for the attacker, a police spokesman said, without identifying him.
Barkan industrial park is adjacent to the settlement of Barkan and was established in the early 1980s.
Most countries consider settlements that Israel has built on land occupied in the 1967 Middle East war as illegal.