Gaza militants targeted Tel Aviv on Friday with another rocket, defying Israeli warnings of a possible ground assault to follow its aerial bombardment of the Hamas-run strip.
Police and a witness said the rocket crashed into the sea off Tel Aviv in the second incident in as many days, as sirens wailed across the city.
Friday's rocket was the farthest one from Gaza that had ever hit inside Israel, and it sparked panic among beachgoers, although several people tried to swim out to the point where the rocket landed, the witness said.
The provocative attack came as world leaders urged Egypt to use its influence with Gaza's Hamas rulers to stamp out the rocket fire that sparked a vast Israeli air offensive launched on Wednesday in which 23 Gazans have already died. Three Israelis were killed on Thursday in one riposte by militants.
Senior Cabinet minister Moshe Yaalon warned that Israel was considering a ground operation in order to stamp out rocket fire.
"We are preparing all the military options, including the possibility that forces will be ready to enter Gaza in the event that the firing doesn't stop," he wrote in a series of postings on his official Twitter account.