World leaders expressed mounting concern about the humanitarian impact of Israel's massive offensive on the Gaza Strip on Monday, as diplomatic efforts to bring an end to the conflict went into overdrive.

Russian President Dmitry Medvedev called for an immediate ceasefire in Gaza during a telephone conversation with Palestinian leader Mahmud Abbas, the Kremlin said.

"Dmitry Medvedev and Mahmud Abbas discussed the escalation of the situation in the Gaza Strip, which has led to numerous victims among the civilian population and a severe humanitarian situation," it said in a statement.

Chinese President Hu Jintao spoke with US President George W. Bush by telephone describing events in Gaza as a "humanitarian crisis", according to Beijing's foreign ministry.

Hu "expressed concern about the escalation in the conflict between the Palestinians and the Israelis and the worsening turbulence in the Middle East," the ministry's website said in a statement.

Aid groups have said Israel's offensive has aggravated a humanitarian crisis for Gaza's population, who have no electricity, no water and now face dire food shortages. Hospitals were only running on back-up generators.

Israel's right to self-defence

Australian Prime Minister Kevin Rudd said it was "critical for Israel to meet its humanitarian obligations".

"Australia recognises Israel's right to self-defence, (but) we call on all parties to avoid any actions which result in unnecessary suffering or increased suffering on the part of innocent civilians," Rudd said.

Jordan's Queen Rania, herself of Palestinian origin, appealed for urgent aid.

"Gaza's children, the dead and the barely living, their mothers, their fathers are not acceptable collateral damage, their lives do matter and their loss does count," said the queen.

She called on governments to contribute to the United Nations' Relief and Works Agency UNRWA emergency appeal for $34-million to meet the immediate needs of Gaza's civilians.

More than 500 Palestinians, including 87 children, have been killed and more than 2500 others wounded since Israel unleashed its "Operation Cast Lead" on 27 December.

A convoy of 80 trucks

Israel has denied there is a humanitarian crisis in the territory.

It allowed a convoy of 80 trucks carrying humanitarian aid to enter the Gaza Strip on Monday, including medicine and food which was sent from Egypt, Jordan, Greece and UN aid agencies, a military spokesperson said.

The Nahal Oz terminal in the north was also opened to allow the transfer of 200 000 litres of fuel for Gaza's electricity station as well as 120 tons of cooking gas, he said.

However, Sigrid Kaag, regional director of the UN Children's Fund (Unicef), warned that "the humanitarian crisis... is hitting children and women most.

"The children in Gaza are currently being deprived not only of the basic human rights any human being should enjoy, but are also being denied the fundamental rights specific to children."

British aid charity Save the Children echoed the UN's concerns over the impact of the conflict on children in Gaza.

Gaza without power

In a statement, the charity warned most homes and hospitals in Gaza are now without power and have no heating. The group stressed that many newborn babies could lose their lives to hypothermia.

"We want (British Prime Minister) Gordon Brown and all EU leaders to push for a ceasefire so that we have safe access to those people in need in Gaza," said a Save the Children spokesperson Dominic Nutt.

Sweden announced it would send around $1.3-million in extra emergency aid to Palestinians in Gaza.

"The situation for the Gaza population is becoming ever more difficult," said the Swedish International Development Cooperation Agency (Sida), a government agency that reports to the foreign ministry.

South Korea offered $300 000 in humanitarian aid, while Japan expressed its concern for the safety of civilians in the Gaza Strip.

"We are seeing violence against violence and hatred intensifying hatred," Chief Cabinet Secretary Takeo Kawamura told reporters.

"The Japanese government is gravely concerned that many victims are civilians as the violence escalates."

Last week, Japan announced $10-million in emergency humanitarian assistance for Gaza.

AFP