Fresh fighting has broken out between government and rebel forces in Chad's capital N'Djamena, reports say.
Heavy weapons fire was heard near the palace where President Idriss Deby is said to be holding out.
Rebels seized large parts of the city on Saturday, but military action subsided overnight as both sides claimed to be in control.
More than 500 French and other foreign citizens have been evacuated to the Gabonese capital, Libreville.
The arriving evacuees appeared "harassed but happy", an AFP news agency journalist in Libreville said.
"It's been a hard, exhausting day. We didn't know how things might turn out," one mother told the agency.
Of the 514 evacuated, 217 were French and the rest included Germans, Belgians, Spanish, Portuguese, Armenians and Egyptians.
About 400 others are gathered in designated areas in N'Djamena, guarded by French troops.
Ceasefire
Witnesses heard anti-tank and automatic weapons fire coming from the city centre, starting at about 0500 local time (0400 GMT).
AFP reported that government helicopters had attacked a column of rebels in the south of the city heading towards the main radio station.
French Mirage combat planes have also been overflying the area.
French officials say Paris is neutral in the military conflict but politically backs Mr Deby's government.
France has also offered to evacuate Mr Deby but he refused to go, French officials told AFP.
Meanwhile French Defence Minister Herve Morin confirmed that the Chadian army chief of staff, Daoud Soumain, had been killed in combat during the rebel advance on the capital.
The fighting comes despite reports of a ceasefire brokered by Libyan leader Muammar Gaddafi.
Rebel spokesman Abderamane Khoulamanla confirmed reports that Colonel Gaddafi had called rebel leader Mahamat Nouri to propose a ceasefire.
"Our leader replied that he would agree to that if his two other partners in the rebellion would agree as well," Mr Khoulamanla said.
'Assault planned'
Another rebel spokesman, Henchi Ordjo, told Reuters news agency that the rebel fighters were simply holding back an assault on the palace to allow the president the chance to leave.
"No ceasefire has been agreed," he said.
The African Union has charged Libya with overseeing the response to the rebellion in Chad, which was condemned at the end of the organisation's summit in Ethiopia.
There was heavy fighting throughout Saturday after thousands of rebels entered N'Djamena in the morning.
They began their advance on the city from near Chad's eastern border with Sudan earlier this week.
There were reports of outbreaks of looting, and of residents cheering on the rebel forces in some areas of the city.
Troubled rule
The BBC's Stephanie Hancock, recently based in Chad, says insecurity has been the hallmark of Mr Deby's 17-year rule.
In 2005, he changed the constitution so that he could run for a third term in office, which sparked mass desertions from the army.
The situation was made worse by the accumulation of oil wealth by Mr Deby and his entourage.
There is also tension with Sudan. Chadian officials say Khartoum is nervous about the deployment of EU troops in Chad and a joint AU/UN force in Sudan's western region of Darfur - both with the mandate of protecting civilians affected by fighting in Darfur.
France dominates the EU force bound for Chad, whose deployment has been delayed because of the fighting.
Some 100 troops Austrian and Irish troops had been due to arrive last Thursday.
Chadian officials have accused the rebels of seeking to stop the deployment of the EU force.
Both the Chadian and Sudanese governments support rebels in each others' territory.
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