An ambulance service spokesman said one of the two was critically wounded.
The Associated Press agency said a police officer was killed in the incident.
Fatal attacks against Israelis in the West Bank have been relatively rare in recent months.
Israeli forces carry out nightly arrest raids in the West Bank, picking up suspected fighters.
On December 28, Palestinian fighters shot and killed two off-duty Israeli soldiers who were hiking in the southern West Bank.
Source: News Agencies