Israeli warplanes, gunboats and artillery units blasted more than 40 Hamas targets on Saturday, including weapons storage facilities, training centres and leaders' homes as Israel's offensive against Gaza's militant rulers entered a second week.
Israeli airstrikes that had waned during the day gathered pace after dark.
One raid hit a mosque in the northern Gaza town of Beit Lahiya, killing 10 people and wounding 33, seven critically, according to a Palestinian health official.
In a sign that the offensive was entering a new phase, Israeli artillery units attacked Gaza for the first time, military officials said.
The shelling was seen as a possible signal that a ground invasion could be nearing.
"We will do all that is necessary to provide a different reality for southern Israel, which has been under constant attacks for the past eight years," Foreign Minister Tzipi Livni told Channel 2 TV.
Israeli defence officials said some 10,000 troops, including tank, artillery and special operations units, were massed on the Gaza border and prepared to invade.
They added that senior commanders are split over whether to send in ground forces, in part because such an operation could lead to heavy casualties but also because they believe Hamas already has been dealt a heavy blow.
Meanwhile, thousands of protesters across Europe staged marches demanding an end to Israel's attacks on the Gaza Strip, which have killed more than 430 people and left 1,700 injured.
In London, several thousand people, many carrying Palestinian flags, marched past Downing Street, while more than 4,000 people demonstrated in Duesseldorf, and some 5,000 in Frankfurt, Germany.
