Israeli troops and Palestinian militants clashed in the central Gaza Strip early Wednesday, after Israeli tanks moved into the area.
Palestinian witnesses and medics say at least three militants -- two from the governing Hamas group -- were killed in the fighting near the Maghazi refugee camp.
Palestinian hospital officials say at least 14 other people, including several children, were also killed in tank firing.
Israel has been pursuing its Gaza offensive in search of a captured soldier, and to stop Palestinian rocket attacks into Israel. Militants captured the soldier and killed two others in a cross-border raid late last month.
Israel pulled troops and Jewish settlers from the Gaza Strip last year after 38 years of occupation.