Tens of thousands of residents and refugees poured out of the city - in cars, on motorbikes, or by foot. Some walked with backs doubled over from bundles of belongings, others dragged children, goats and pigs away from advancing rebel troops.
Goma's governor, Julien Mpaluku, acknowledged that panic was spreading in the eastern provincial capital. He said he could not confirm that the army had deserted Goma, but stressed that U.N. peacekeepers were still in charge and that rebels had not yet entered the city.
Still, the U.S. embassy said its officials were leaving Goma and urged all American citizens to follow. Hundreds of foreign aid workers were also trying to evacuate.
Rebel leader Laurent Nkunda has threatened to take Goma despite calls from the U.N. Security Council for him to respect a U.N.-brokered cease-fire signed in January.
"We are not far from Goma, but because there is a state of destabilization in the town we decided in our movement to cease fire and unilaterally to proclaim a cease-fire," Nkunda was quoted as saying by the BBC.
Nkunda called on government forces to follow suit, the BBC said. U.N. spokesman Madnodje Mounoubai confirmed the rebels were not in the city and said peacekeepers were at the airport and in other strategic points.
"What we fear is that if Gen. Nkunda takes the town, is that there will be chaos ... and maybe even killing on a large scale," Sir John Holmes, the U.N.'s under-secretary-general for humanitarian affairs, told Britain's Channel 4 News from New York.
Refugees said the Tutsi rebels had already overrun Kibati, a village seven miles (12 kilometers) north of Goma. About 45,000 people fled the Kibati camp in a matter of hours Wednesday, according to the U.N. High Commissioner for Refugees.
"It was very chaotic," U.N. refugee spokesman Ron Redmond said. "People began leaving the camp in a panic."
Some refugees from Kibati were among those streaming later through Goma, desperately trying to find a safe place.
The U.N. says its biggest peacekeeping mission - a 17,000-strong force - is now stretched to the limit with the surge in fighting and needs more troops quickly. Troops from India, Pakistan, Bangladesh, Uruguay and South Africa make up most of the existing force.
But hopes for immediate backup from the European Union dimmed. French Foreign Minister Bernard Kouchner said Wednesday that EU had considered sending troops to reinforce U.N. peacekeepers in Congo but "a certain number of countries refused." He offered no further details.
There were also fears the fighting could explode into a conflict that dragged in neighboring African countries.
The Congolese army said troops from Rwanda had crossed the nearby border and attacked its soldiers earlier Wednesday, a charge that Rwanda's Tutsi-led government immediately denied. Still, Congo turned to neighbor Angola for help "defending territorial integrity."
Congo suffered through back-to-back wars from 1996 to 2002 that embroiled eight African nations and became a rush at the country's vast mineral riches.
U.N. Secretary-General Ban Ki-moon said Wednesday he was speaking to the presidents of Congo and Rwanda to resolve the crisis and that Europe and the United States plan to send diplomats to try to negotiate a peaceful solution.
The U.S. State Department said Assistant Secretary of State for African Affairs Jendayi Frazer would arrive in the the Congolese capital of Kinshasa on Thursday.
"There is a lot of violence," said department spokesman Sean McCormack. "This is of deep concern to us."
Government soldiers entered Goma along with the fleeing refugees, grabbing private cars, taxis and motorbikes to speed their retreat.
Gunfire crackled in several northern neighborhoods of Goma, residents said by telephone, speaking anonymously in fear of retaliation. One man said he had to run behind a wall to escape a barrage of gunfire from Congolese army troops.
Residents holed up in their houses, fearing army troops would loot on their way out.
Soldiers briefly hijacked a car carrying an AP cameraman and photographer and demanded to be driven about 50 miles (80 kilometers) to the town of Saki. But the soldiers fled after learning that the rebels were only a few hundred yards away.
Nkunda says the Congolese government has not protected his minority Tutsi tribe from a Rwandan Hutu militia that escaped to Congo after helping carry out the 1994 Rwanda genocide in which half a million Tutsis were slaughtered.
The U.N. peacekeeping force's failure to halt the rebellion has enraged ordinary Congolese, some of whom attacked U.N. compounds in Goma with rocks this week.
A bombardment outside Goma in the morning frightened thousands of refugees and stirred growing anti-Tutsi sentiment in a region where decades of conflict with the majority Hutu reached a cataclysm in the 1994 genocide.
"It's the 'long noses' from Rwanda who are bombing us, the Rwanda Tutsi," refugee farmer Gaspar Sebigore shouted. In the days after Rwanda's genocide, more than a million Hutus fled to Congo where they regrouped in a brutal militia that helps fuel the continuing conflict in eastern Congo.
"(Congo's army) wants to divert the international community's attention from the fact that they are collaborating with the masterminds of the Rwandan genocide," Rwandan Maj. Jill Rutaremara told The Associated Press.
On the Web:
The U.N. mission in Congo: http://www.monuc.org
Associated Press writers Malkhadir M. Muhumed in Nairobi, Hrvoje Hranjski in Manila, Philippines, Siona Casimiro in Luanda, Angola, Alexander G. Higgins in Geneva, Edith M. Lederer at the United Nations and Eddy Isango in Kinshasa, Congo, contributed to this report.