premise: Heavy fighting resumed in central Somalia Wednesday after retreating Islamist fighters opened fire on a force of government and Ethiopian troops, officials and residents said, as the conflict in the Horn of Africa nation entered its second week.
  Hours after the UN Security Council failed to agree on the withdrawal of foreign troops, Islamists fighters in trenches near the town of Jowhar opened fire to stop Somali-Ethiopian troops from advancing further southwards.
  "Very heavy fighting has erupted outside Jowhar. The Islamic forces say they will keep fighting," said Mohamed Abdi Ali, a resident of the town about 90 kilometres (55 miles) north of the Islamist-controled capital of Mogadishu.
  "Ethiopians have not started using planes yet, but we do not rule that out," he added.
   What will happen if the UN security council did not fail to reach for an agreement?
hypothesis: withdrawal of foreign troops