GAZA, Sept 27 (Reuters) - Israeli forces pulled back on Thursday after a raid into the northern Gaza Strip a day earlier in which troops killed 11 people in clashes with local gunmen and prompted calls for revenge from Hamas militants. The Islamist group, which seized control of Gaza from rival forces loyal to Palestinian President Mahmoud Abbas in June, vowed revenge, and said Israel would "pay heavily" for the attack. "The resistance factions are ready to force the Zionist enemy to pay a heavy price if they pursue their aggression. All options will be open to the factions in order to defend our people," said Hamas spokesman Sami Abu Zuhri. Israel launched the raid into the northern Gaza town of Beit Hanoun on Wednesday, following a surge in cross-border rocket salvoes. Palestinian militants fought back. Witnesses said Israeli troops pulled back to positions they held earlier inside the coastal territory. At least 21 Palestinians were also wounded in some of the fiercest fighting since Hamas seized control. One Hamas militant who was wounded on Wednesday died in hospital early on Thursday. Israel, which last week declared Gaza an "enemy entity", has signalled that it could order its forces in to seize areas used for launching improvised, short-range rockets into Israel: "We are getting closer to carrying out a widespread operation in Gaza," Defence Minister Ehud Barak said on Wednesday. Israel withdrew troops and Jewish settlers from the coastal enclave in 2005, though it retains control of its air, land and sea borders. The government said last week it was considering cutting energy and other supplies to the territory's 1.5 million people because of the continuing rocket fire.
