The Israeli military yesterday said Palestinian militants had fired 11 rockets, ending an overnight lull and adding to more than 110 launched in the preceding 72 hours.
One hit a house in the town of Netivot, causing damage but no injuries.
Six Palestinians have been killed by Israeli shells fired on Gaza, including four civilians, and 40 wounded.
Eight Israelis have also been wounded in the cross-border attacks.
"We have a full box of tools... that we have not yet used," Israeli Vice-Prime Minister Moshe Yaalon said. "We will need to toughen our response until Hamas says 'enough' and ends the fire."
Hamas did not claim responsibility for yesterday's attacks, suggesting it was looking to step back.