Tripoli, Libya (CNN) -- Heavy, sustained gunfire rang out in the Libyan capital of Tripoli early Sunday morning as unrest in the country entered a 20th day. On Saturday, Libyan opposition leaders announced an alternative government as the United States and other countries helped evacuate refugees of the conflict. Anti-government forces also claimed two major successes Saturday: preventing pro-government forces from taking the city of Zawiya, near the capital of Tripoli, and capturing the strategic eastern oil town of Ras Lanuf. The opposition and government forces have battled in recent days for full control of Zawiya, about 30 miles west of Tripoli.
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NEW: Heavy, sustained gunfire is heard in the capital city of Tripoli
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Gadhafi's foes announce the formation of body to represent Libya
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Opposition members in the east say a military plane was shot down
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Almost 200,000 people have fled the situation in Libya
The fierce fighting has sparked the flight of @placeholder and foreigners out of Libya, with nations across the globe scrambling to help people leave.