GAZA CITY (AFP) — Israeli warplanes carried out intensive raids on Hamas targets on Monday as ground troops surrounded Gaza's main city, while Israel faced mounting diplomatic pressure for a ceasefire.

The senior Hamas leader in Gaza promised "victory is coming" for the Islamist group, but Israel's defence minister said "we have hit Hamas hard" while insisting the operation to halt Hamas rocket attacks would continue.

Israel, under pressure over the mounting toll on civilians, agreed to let food and fuel into Gaza but about 200 trucks were stuck at the border as the military said no one turned up to receive the supplies.

Thousands of ground troops intensified their move into the Palestinian enclave of 1.5 million people, battling Hamas fighters in the east of the territory as they tightened their grip around Gaza City.

Israeli jets carried out more than 30 air strikes. The military said they hit a mosque in the northern town of Jabaliya "where arms were being stored, as well as houses containing arms caches and vehicles that were transporting rocket launchers and armed men."

Naval ships off the coast also bombarded targets to help the ground force advance launched on Saturday night.

The Israeli strikes killed another 14 Palestinians, including five children, on Monday, medics said.

Three children were killed by a tank shell in Zeitun and two were killed in Shati by a naval strike, according to the head of Gaza medical emergency services Moawiya Hassanein.

More than 520 Palestinians -- including at least 90 children -- have been killed since Israel launched Operation Cast Lead on December 27 with about 2,500 wounded.

Israel says dozens of Hamas fighters have been killed while one Israeli soldier has been reported dead and 55 wounded since Saturday.

Defence Minister Ehud Barak told parliament the Hamas war would go on.

"Gaza City is partially surrounded," Barak told deputies. "We have hit Hamas hard, but we have not yet reached all the goals that we have set for ourselves and the operation continues," he said.

"We are doing everything that a state must do to protect its citizens," he said. "We want that the attacks against our citizens and our soldiers stop."

Three civilians and one soldier have been killed by rockets fired from Gaza since Israel's operation started. More than 10 rocket and missile attacks were reported Monday.

Hamas remained defiant. "Victory is coming, God willing," the movement's senior leader in Gaza, Mahmud Zahar said in a television address.

Israel faces intense international pressure to agree a ceasefire and ease the suffering of the Gaza population which has no power or water supplies and endures a daily struggle to get food, according to aid agencies.

Israel agreed to let 200 trucks cross into Gaza on Monday but the military said no one turned up on the Palestinian side to receive the supplies.

French President Nicolas Sarkozy was due to hold talks with Israeli and Palestinian leaders on Monday on ways to seek a ceasefire.

An EU ministerial delegation and a Russian envoy were also due in the region. US Secretary of State Condoleeza Rice called off a trip to China because of the Gaza crisis.

France's Sarkozy was scheduled to meet Israeli Prime Minister Ehud Olmert in Jerusalem and Palestinian president Mahmud Abbas in Ramallah, after a first meeting with Egyptian counterpart, Hosni Mubarak, in Cairo.

Czech Foreign Minister Karel Schwarzenberg, whose country holds the rotating EU presidency, is heading a delegation to the Middle East, while Russian President Dmitry Medvedev's Middle East envoy, Alexander Saltanov, was also on the way.

The European Union and Russia are both part of the Middle East diplomatic Quartet, along with the United Nations and the United States.

UN Secretary General Ban Ki-moon said Sunday he would be working with key players on ways to end the violence.

The Israeli offensive has sparked spiralling anger in the Muslim world and protests across the globe.