The United States said libyacould sink into civil war unless the Libyan leader ends his four-decade rule amid fears that the uprising, the bloodiest yet against long-serving rulers in the Middle East, could cause a humanitarian crisis.
Gaddafi is defiant and his son, Saif al-Islam, has warned the West against launching military action. He said the veteran ruler would not relinquish power or be driven into exile.
Across Libya, tribal leaders, officials, military officers and army units have defected to the rebel cause and say they are becoming more organised. Tripoli is a stronghold for Gaddafi in this oil-producing north African state.
"We are going to keep the pressure on Gaddafi until he steps down and allows the people of Libya to express themselves freely and determine their own future," Susan Rice, the US ambassador to the United Nations, told ABC's "Good Morning America".
Captain Faris Zwei, among officers in the east who joined the opposition to Gaddafi, said there were more than 10,000 volunteers in Ajdabiyah, 500 miles from the capital.
