U.N. Secretary-General Ban Ki-moon is gravely concerned about continued fighting and aheavy death toll in Mogadishu, Somalia that has forced more than 320,000 people to flee over the past six days, U.N. spokeswoman Michele Montas said Monday. Ban deplores the reported indiscriminate use of heavy weapons against civilian population centers, which is in disregard of international humanitarian law, Montas told reporters. Ethiopian troops in the country have stepped up their battle in the nation s traditional capital against insurgents. At least 250 people have been killed since the fighting started, humanitarian workers in Mogadishu said. Ban said that there was no military solution to the Somali conflict and renewed his call for an urgent resumption of political dialogue. Political talks among all parties are scheduled for next month.