GENEVA - The UN Security Council should be convinced of the need for a ceasefire in the besieged Syrian enclave of eastern Ghouta, where at least 370 people have reportedly been killed, the UN humanitarian coordinator for the Syria crisis said on Thursday."After all the images that came out of east Ghouta in the last 72 hours, if this is not going to convince Council members, Council states, of the need for a ceasefire, honestly we don't know what is it that would convince them," Panos Moumtzis said."It feels like nobody's listening, there's no reaction, there's no political strength and ability to bring an influence, to bring a halt to an extreme offensive which is affecting civilians," he told Reuters via Skype from Kuwait, where humanitarian donors have been meeting.The UN needs $3.5 billion for 2018 but the plan is only 5 percent funded so far, he said.Some 390,000 trapped civilians are afraid to venture out of their houses, and water, food and electricity supplies have run out, Moumtzis said. In one area, Harasta, 80 percent of people were living in basements.Half of the population are children, he said.The enclave has been besieged by Syrian government forces since 2013, but they have massively stepped up their attacks this year and intensive aerial attacks were occurring "minutes apart", Moumtzis said.If there was a ceasefire, the UN could enter with food and medical supplies which are just minutes away, and evacuate the critically sick and injured. But the Syrian government has not given the necessary authorisation for an aid convoy, he said.There is no plan for a mass evacuation, which could only be done voluntarily, partly because there is nowhere to go.People from several previous sieges have been evacuated to Idlib governorate, which is now congested, with over 350,000 displaced since December. It is also a war zone, with pro-government forces attacking rebels."If this continues we could potentially have 2 million people stranded at the border with Turkey," Moumtzis said.More than 500,000 are also displaced around Raqqa, which was recaptured from Islamic State last year. Despite the risk of unexploded bombs and booby-traps, 60,000 people have gone back.Moumtzis said there were 50-70 casualties in Raqqa every week, compared to 50 per year in the whole of Afghanistan.