Israeli forces pounded Palestinian houses, mosques and smuggling tunnels from the air, land and sea in the Gaza Strip yesterday, killing at least seven children as they pressed a bruising offensive against Hamas fighters.

Israeli Defense Minister Ehud Barak said the campaign would continue till Israel achieved "peace and tranquility" for people in southern Israel, who have been bombarded by Palestinian rockets.

But far from backing down, Gaza's Hamas urged Palestinians to "crush" the invading forces and target Israeli civilians.

A stream of diplomats and world leaders hoping to end the violence headed for the region to meet with Israeli leaders as outrage over rising Palestinian casualties mounted.

Gaza health officials said Israeli attacks that began on December 27 had killed 537 people and left about 2,000 injured. At least 200 of the dead were civilians.

Israeli forces seized sparsely populated areas in northern Gaza on Sunday and circled Gaza City, the territory's biggest town. Further movement into built-up areas would mean even deadlier urban warfare, replete with house-to-house fighting and sniper fire in crowded streets and alleyways familiar to Hamas' 20,000 fighters.

Israeli forces have been training in a mock Arab city for more than two years to prepare them for the urban battle they would encounter in Gaza, military spokeswoman Maj Avital Leibovich said. But she did not say whether troops would definitely enter Gaza's cities.

Thirteen civilians died in attacks across Gaza yesterday morning, said Gaza health official Dr Moaiya Hassanain.

Explosions could be heard in Gaza City as aircraft attacked buildings. Unmanned Israeli planes and Apache helicopters circled overhead, with the streets of Gaza City, home to 400,000 people, being almost empty.

Questions:

1. What is the name of the Israeli Defense Minister?

2. How many fighters does Hamas have?

3. Israeli forces were training where for more than two years?

Answers:

1. Ehud Barak.

2. 20, 000.

3. A mock Arab city.