Three more airstrikes shook Gaza early Friday morning, following Israel's attack in the Gaza Strip on Thursday. The Israeli military did not immediately confirm the latest strikes, though Thursday's bombing—which killed the chief of a militant Palestinian group—was an act of retaliation after a series of terror attacks in Israel left seven dead and 25 injured. The attacks began when gunmen fired on a tourist bus in the resort town of Eilat. Within an hour, explosives were detonated near a military patrol traveling along the border with Egypt. Israeli Defense Minister Ehud Barak said the attack “reflects the weakening of Egypt's hold in the Sinai and the broadening of activities by terror elements." Hamas in Gaza denied responsibility, but said it would fight back if Israel attacked it. U.S. Secretary of State Hillary Clinton condemned the terrorist attacks and echoed Barak's concerns about the Sinai, urging the Egyptian government to find "a lasting solution."