It's day seven into Israel's offensive against targets in the Gaza Strip and Israeli warplanes have carried out more air strikes while Palestinian militants have launched further rocket attacks into Israel. The Islamist group Hamas has vowed revenge and called for mass protests against the Israeli actions.

A cloud of smoke rises following an Israeli missile strike in the northern Gaza Strip, 02 Jan 2009

Israel said its aircraft struck a number of militant targets in Gaza Friday, including a mosque in Jabaliya, which Israeli officials say was used to store rockets and other weapons.

Israel has hammered sites throughout the Gaza Strip and says it will continue to do so until Islamist militants stop firing rockets into Israel.

Israeli government spokesman, Mark Regev, says Hamas brought this situation on by not agreeing to extend a truce with Israel that expired in December.

"Hamas escalated the situation last week with their rocket barrages against Israeli civilians," he said. "Hamas has no one but itself to blame for the current situation if finds itself in."

Gaza officials say more than 420 Palestinians have been killed in the Israeli strikes and more than 2,000 injured. U.N. officials estimate that about a quarter of those killed are civilians.

On Thursday an Israeli warplane bombed the home of a senior Hamas leader, killing him, his family and several neighbors. Nizar Rayyan was an outspoken advocate of renewing suicide bombings.

Following his death, militants vowed revenge. Hamas spokesman Ismail Radwan said all options are on the table.

Radwan said the killing of Rayyan was a crime. He added that options for revenge include suicide bombings and striking at Israeli targets everywhere.

Hamas called for mass protests against Israel's actions. Braced for demonstrations, Israel closed off the occupied West Bank until Saturday night and stepped up security checkpoints.

Israel agreed to let a several hundred foreign passport holders leave Gaza on Friday. They leave behind 1.5 million Palestinians, and there is a growing sense that some sort of Israeli ground offensive into Gaza may be imminent.