IN the killing streets of this seaside capital, many children are dying or being maimed in a vicious civil war, while the world's diplomats look the other way.After four weeks of intensified clan fighting that has claimed thousands of civilian casualties, no nation or organization has offered to mediate a settlement. Amid the continuing, random shelling, Somali residents, Western medical workers here, and others are asking: Where is the United States? Where is the United Nations? Where is the Organization of African Unity? Mary Racelis, regional director in East Africa for UNICEF, the UN agency devoted to helping children, says first the Gulf war and now the civil war in Yugoslavia have distracted journalists and diplomats from paying attention to Somalia. "Is Africa not so important?" she asks. The effects are felt by a twelve-year-old Somali, Bibi Abukar Muse, who is trying to learn to walk on one leg, with the aid of crutches. "I was in the market when a rocket came in," she says, leaning against a wall in a crowded hallway of a hospital here. To save her life, doctors had to amputate her leg. Outside the hospital, in a tent for overflow casualties, 17-year-old Hussein Mohammed lies on the sand, waiting for more medical help. Hussein's right leg is tied to a splint, and he has other bullet wounds from automatic weapons fired by robbers who invaded his family's home Dec. 11. Fatuma Abukar, in another hospital, has lost five of her 10 children. "I was in my house," she says "preparing pasta for my children. It was 1 p.m. Then heavy artillery came. I don't know where it came from." Three of her children were killed outright; two more died later. Several of her surviving children are injured. "I've already lost five children," Mrs. Abukar says. "The only thing that I need is peace." But peace seems far away. In January, after a month of fierce fighting in Mogadishu, Somali rebels forced longtime dictator Mohamed Siad Barre to flee the capital in a tank convoy. A few days later, Ali Mahdi Mohamed, a Mogadishu hotel owner and a financial backer of the rebel United Somali Congress, was named president by the USC. This angered Gen. Mohamed Farrah Aidid, military commander of the USC. General Aidid and other leaders felt a president should be named only at a national conference of rebel and other political leaders. Mr. Mahdi and Aidid belong to different subgroups of the Hawiye clan of central Somalia, which formed the USC to oust former President Barre. The two men fell out over alliances with the armed groups of other major clans. In July, Mahdi was confirmed president at a meeting of most of Somalia's political and ethnic leaders - a meeting marked by the absence of General Aidid and representatives of the Somali National Movement. The SNM has declared Somalia's northern region independent from the south and has avoided the fighting afflicting the rest of the country. In November, Mahdi tried unsuccessfully to have a plane load of Somali money that had been printed in Europe flown into Mogadishu to help meet his administration's mounting bills. Aidid accuses Mahdi of corruption. USC soliders threatened to shoot the plane down. Mahdi responded with a show of force, and fighting between troops loyal to Aidid and Mahdi broke into full-scale battles in mid-November. A front line, or no-man's land was quickly established in the city, with each side randomly firing heavy artillery into the opposing side. As many as 200,000 civilians may have fled to the outskirts of Mogadishu, where they live in squalor, under trees or sheets of plastic, and, like those still remaining in the captial, are running out of food. Preferring the risk of bombs to starving under trees, many Somalis, like Omar Osman, stay in their homes. In the old section of Mogadishu, not far from the front line, he makes a plea to the world: "We are going to die of hunger. We ask the United Nations, the OAU to help us - immediately. We are very weak." Because of the lawlessness throughout Somalia it has been difficult for aid agencies to get food and badly needed medical supplies into the country. So far, the UN, the Organization of African Unity, and non-African Muslim countries (Somalia is almost entirely Muslim) have failed to offer any help in trying to halt the fighting, says Aidid, who vows to continue the battle until Mahdi is defeated. The US announced this week that it was increasing aid to Somalia by $19 million because of the UN's refusal to organize significant aid for the beleagured country. A US State Department official describes the battle for Mogadishu as "The most acute humanitarian crisis in the world at the moment." And a spokeswoman for the International Committee of the Red Cross in Geneva, calls it "One of the worst wars we have known at least in this century." UNICEF has provided some medical supplies used by relief groups working in Mogadishu, including Medecins Sans Frontieres (Doctors Without Borders). But UNICEF regional director Racelis says the UN, including UNICEF, or the United States also has a "clear possibility" of mediating a settlement if a mediator acceptable to both sides can be found. Another senior UN official told the Monitor: "There's been window after window of opportunity [for outside mediation], but no one has come in." The State Department officia, says US officials are "looking for options - both humanitarian and political."