At least three children were among the 12 Palestinian civilians killed in the latest Israeli attacks on Gaza. Palestinian medical officials said seven members of a Palestinian family were killed in a strike on their home at Beach refugee camp. The attack, on the outskirts of the city of Gaza, followed a separate shelling which killed three children and their mother in the Zeitoun neighbourhood, medical officials said. Meanwhile, hundreds of Israeli troops are moving deeper into Gaza as the second day of the ground assault gets under way. Supported by bombardments from land and sea, they have taken up positions on either side of Gaza City. The move follows a week of airstrikes - that have killed more than 500 Gazans and wounded around 1,700 others - which Israel says are aimed at stopping Hamas rocket attacks. At least 50 people - including many Palestinian civilians - were killed on Sunday. International pressure to secure a ceasefire in Gaza is growing as it teeters on the brink of a humanitarian disaster. Aid agencies have warned that people in the region are facing "grave" shortages of food and water. Hundreds of Israeli troops have poured over the border in a ground offensive which has left Gaza City paralysed as it is pounded with artillery. Save the Children has warned that basic humanitarian supplies are running out with much of the city left without electricity and water. The agency called for aid to be let in to the stricken area and said that 50,000 children are already suffering from chronic malnutrition. More than 2,000 families were displaced prior to the launch of the ground offensive on Saturday with charities expecting the number to increase significantly as fighting escalates. Politicians led by Prime Minister Gordon Brown have united to urge both sides to reach an immediate ceasefire. Mr Brown said it was vital that the international community, including the Arab League, worked together to find a workable solution to the problem. He said: "This is a very dangerous moment, I think everybody around the world is expressing grave concern. "What we've got to do almost immediately is to work harder than we've done for an immediate ceasefire."