Israel is "prepared to escalate" its response to Palestinian rocket fire, Prime Minister Benjamin Netanyahu warned on Sunday, after one of the worst flare-ups along its border with Gaza in recent years.
"The army is acting and will act forcefully against the terror organisations in the Gaza Strip. They are receiving strong blows from the army," Netanyahu told ministers at the beginning of his cabinet meeting.
"The world must realise that Israel won't sit by idly in the face of attempts to attack us. We are prepared to escalate our actions," he said.
The flare-up began on Saturday evening when Gaza militants fired an anti-tank missile at an Israeli jeep along the Gaza border, injuring four soldiers, one of them severely. Three remained in hospital on Sunday.
Israel retaliated with airstrikes, shelling and artillery fire that left six Palestinians dead and 32 injured by Sunday morning, and Palestinian militants fired at least 57 rockets into southern Israel.
The latest barrage of rockets, on Sunday morning, hit the Israeli border town of Sderot, injuring four civilians, Israeli police said.
The outbreak of violence was one of the most serious since Israel's devastating 22-day operation in the Gaza Strip over New Year 2009, and raised the spectre of a broad Israeli operation against the Palestinian territory.
"It's a very severe situation, rockets are landing on our towns and villages, almost on a daily basis and of course no democratic country can tolerate such a thing," finance minister and Netanyahu confidant Yuval Steinitz said.
"If this will proceed, we will consider a much stronger and massive retaliation in order to protect our citizens."
The flare-up comes ahead of Israeli elections in January, but ministers said the build-up to the vote would not prevent an operation if it was necessary.
"Israel will have to prepare itself for an operation, whether or not elections (are scheduled)," infrastructure minister Uzi Landau said at the beginning of the cabinet meeting.