( CNN ) -- Rebel forces defending the Libyan city of Misrata from government troops are making `` meter-by-meter '' gains despite heavy shelling and rocket attacks , a Western journalist inside the city said Tuesday . Units that remain loyal to longtime Libyan strongman Moammar Gadhafi have been firing rockets and artillery shells into residential neighborhoods , leaving a nearby emergency room full of women , children and old men , Marie Colvin , the Middle East correspondent for Britain 's Sunday Times , told CNN . `` The rebels are very much trying at a minimum to push back Gadhafi 's lines so he simply ca n't do that , '' Colvin said . Meanwhile , the rebels are asking why NATO forces are n't targeting the pro-Gadhafi gunners . NATO warplanes and missiles have been pounding Gadhafi 's forces since March as Gadhafi 's troops try to quash a nearly 3-month-old revolt against his regime . In Misrata , two months of fighting and the ongoing shelling of the city 's port have prevented most aid ships from docking there , leaving the city `` at the forefront '' of U.N. humanitarian concerns , a top U.N. official told the Security Council on Monday . A ship carrying aid from the International Committee of the Red Cross docked in Misrata on Tuesday , but the ongoing fighting has deterred many captains from trying to enter the port , Colvin said . The ICRC said the vessel carried medical supplies , spare parts to repair water and electrical supply systems and 8,000 jars of baby food . Meanwhile , on the front lines of the battle , bullets are whizzing past `` like very angry hornets , '' Colvin said . At least 70 rebels have been wounded -- but they have held their line , `` and meter by meter were able to advance , '' she said . `` They 're defending their homes . They 're defending their families , and they are not giving up an inch . They are fighting , '' Colvin said . The first shipment of nonlethal aid from the United States to the Libyan opposition arrived Tuesday in Benghazi , U.S. State Department spokesman Mark Toner said . It included more than 10,000 MREs -- meals ready to eat -- that are halal , permissible under Islamic law . Other items en route from the U.S. Defense Department include medical supplies , tents , uniforms , boots and personal protective gear . U.S. officials are coordinating with the opposition Transitional National Council `` to determine what additional assistance requirements we might be able to support in the coming weeks , '' Toner said . Almost 750,000 people have fled the country amid the fighting , and another 58,000 are displaced within Libya , Valerie Amos , the U.N. undersecretary-general for humanitarian affairs , told the Security Council on Monday . Another 5,000 are stranded at border crossings between Libya , Tunisia and Niger , Amos said . Others have tried to flee by sea , but one such attempt appears to have ended in disaster for hundreds of refugees as their ship capsized off the capital , Tripoli . Somalia 's ambassador to Libya , Abdelghani Mohamed Oweys , said the vessel that overturned Friday was carrying more than 600 asylum seekers from various Arab and African nationalities , including 240 Somalis . The total number of casualties is unknown , but Oweys said at least 54 Somalis were dead or feared dead Tuesday . Laura Boldrini , spokeswoman for the Office of the U.N. High Commissioner for Refugees in Italy , said 16 bodies had been pulled out of the water from the Tripoli harbor . `` From what refugees are telling us , the Libyan authorities are facilitating the departures of non-Libyan citizens from Libyan coasts , '' Boldrini said . `` Refugees are not considered at all as humans . Trips are organized on unlikely vessels , and they leave Libya without considering the weather forecast . '' Since the end of March , two vessels departing from Libya have disappeared -- one carrying 320 people and the other 160 , Boldrini said . In addition , `` We know of a shipwreck on April 4 , where 250 people died , '' Boldrini said . Fighting between government and rebel troops also raged on in al-Brega , a key oil town in eastern Libya . Three rebels have died in clashes with Gadhafi forces since Monday , according to rebel spokesman Mostafa Bozen and a rebel fighter on the front lines , who spoke to CNN on condition of anonymity for safety reasons . Al-Brega is held by pro-Gadhafi forces , and the rebels have made multiple unsuccessful attempts to enter the town , the sources said . CNN 's Nima Elbagir , Jomana Karadsheh , Antonia Mortensen , Sara Sidner and Amir Ahmed and journalist Livia Borghese contributed to this report .
NEW : Gadhafi 's gunners pound Misrata neighborhoods , journalist says . NEW : Despite the bombardment , the rebels `` are not giving up an inch '' A Red Cross aid ship docks in Misrata , while U.S. aid reaches Benghazi . 54 Somalis are dead or feared dead in the latest refugee boat tragedy from Libya .