Palestinian militants barraged Israel with more than 200 rockets on Thursday, killing three people as Israel pressed a punishing campaign of airstrikes on militant targets across the Gaza Strip. Three rockets targeted the densely populated Tel Aviv area, setting off air raid sirens in brazen attacks that threatened to trigger an Israeli ground invasion of Gaza.

Late in the day, Israel signaled a ground operation may be imminent as forces moved toward the border area with Gaza. At least 12 trucks were seen transporting tanks and armored personnel carriers, and a number of buses carrying soldiers arrived. Israeli Defense Minister Ehud Barak said he had authorized the army to call-up additional reservists for possible action. The army said it was prepared to draft up to 30,000 additional troops.