GENEVA (Updated 2) - At least 20 children have been killed in weeks of fighting in the besieged western Libyan town of Misrata, the UN Children's Fund (UNICEF) said on Tuesday. "Fifty days into the fighting in Misrata, the full picture of the toll on children is emerging – far worse than we had feared and certain to get worse unless there is a ceasefire," UNICEF spokeswoman Marixie Mercado said. "We have at least 20 verified child deaths and many more injuries due to shrapnel from mortars and tanks and bullet wounds," she told a news briefing in Geneva. The youngest victim was nine months old and most of the children killed in the past two weeks were younger than 10 years old, she said, citing information from doctors in Misrata. "Many other children are traumatised by what they see and hear," Mercado said. Forces loyal to Muammar Gaddafi renewed bombardment of Misrata on Tuesday and casualties were seen being taken to hospital, an Amnesty International researcher in Libyan's third largest city said. Doctors from the Arab Medical Union who are deployed at Misrata hospital told the World Health Organisation (WHO) the 120-bed hospital there was "overwhelmed". "They have difficulties in conducting surgery because the capacity is overstretched and 120 patients need evacuation," WHO spokesman Tarik Jasarevic told reporters. An average of 30 patients with multiple injuries and requiring surgery are admitted every day there, the WHO spokesman quoted the doctors as saying. There was also an urgent need at Misrata hospital for medical supplies to treat vascular diseases, diabetes, hypertension and cancers, he said. The agencies did not have exact figures for casualties in Misrata but said many wounded had been evacuated. Some 50 patients were evacuated from Misrata on Monday by health personnel from the eastern rebel-held cities of Tobruk and Benghazi. This followed the evacuation of 73 wounded by humanitarian agencies over the weekend. Burn patients who cannot be treated in Benghazi are being taken by ambulance to Egypt, according to the WHO.