The Israeli raid, involving infantry, armor, and aircraft, is being conducted in a border area, close to the Bureij and Magazi refugee camps.
Six of those killed were members of Azzedine al Qassam, a paramilitary wing of the Hamas movement. Among at least 15 wounded was a local TV cameraman with the Al Aqsa channel, who had his leg amputated, his colleagues told a RIA Novosti correspondent.
Two Israeli soldiers were also wounded when their armored bulldozer came under grenade gun fire, a spokesperson for the military told RIA Novosti.
Hamas established control of the Gaza Strip in June after defeating supporters of a rival movement, Fatah, and Palestinian leader Mahmoud Abbas over a week of bloody clashes.
Israel, whose massive military operation is aimed against Hamas, rejected proposals of a truce with Palestinians following rocket attacks in Sderot, eastern Israel last November. The Israeli government also announced its intention to resume the policy of "pinpoint killings" of Palestinian leaders.
