Israel attacks key Hamas sites

Air force jets bombed the Hamas-run interior ministry as part of Israel's attempts to stop Gaza's ruling body from launching rocket attacks.

Doctors in Gaza said the three-day death toll had risen to 315, including seven children under the age of 15 who were killed in two separate strikes.

Most of those killed since Saturday were members of Hamas security forces, although the precise numbers remain unclear.

The UN agency in charge of Palestinian refugees says at least 51 of the dead have been civilians. A rise in civilian casualties could intensify international pressure on Israel to abort the offensive.

The continuing campaign comes despite Foreign Secretary David Miliband joining other international calls for an immediate halt to the violence.

Israel also looks poised to launch a ground assault on the Gaza strip after the country's leaders approved a call-up of 6,500 reserve soldiers. The country has also doubled the number of troops on the Gaza border in the past two days, and deployed an artillery battery.

Israel has said it is responding to Hamas-led rocket attacks on the southern part of the country, which have recently surged in numbers since a six-month ceasefire agreement expired last week. On Sunday jets targeted smuggling tunnels in Gaza, a central prison and Gaza's Islamic University - a noted cultural symbol for Hamas.

Israel has insisted it will keep up the assault until militants stop launching rockets, with defence minister Ehud Barack warning ominously that "the time has come to fight" and signalling willingness to put "boots on the ground".

Meanwhile there were reports that the Israeli navy had begun bombarding the area from the sea.