The international Red Cross said Tuesday it was preparing to fly 11 tons of medical supplies to Israel to help Gaza's over-stretched hospitals. The charter plane is scheduled to leave Geneva for Tel Aviv late Tuesday, said Florian Westphal, a spokesman for the International Committee of the Red Cross. Westphal said the supplies were destined for Gaza hospitals struggling to treat hundreds of people wounded in IDF's Operation Cast Lead. Westphal said six trucks full of medical supplies and spare parts for ambulances and generators would arrive in Gaza from Israel on Tuesday. A Red Cross delegation that visited Gaza's largest hospital, Shifa, found conditions there had stabilized, he said. "The situation is difficult but increasingly under control," Westphal told The Associated Press. Ensuring that hospitals have sufficient fuel is a priority because many rely on diesel generators for electricity, he said. The agency also has put a surgical team on standby to fly to Israel once it receives the green light from Israeli authorities. Other aid agencies have also scaled up their response to the situation in Gaza. The World Health Organization said it was preparing to fly 50 surgical kits from Norway to Israel. The kits will contain enough supplies to treat 5,000 wounded people. The health organization is also shipping nine basic health kits to Gaza - enough for three months' treatment of 90,000 people for common illnesses.