France says a sandstorm is preventing its forces from entering the last major town in northern Mali in their offensive against Islamist militants, reports BBC News.
The troops remained "blocked" at the airport in Kidal, the French defence minister said.
His statement appeared to conflict with earlier reports that French troops were in the town and militants had left.
French and Malian forces have been sweeping north, earlier taking Gao and Timbuktu with almost no resistance.
The retreating Islamist militants have been accused of destroying ancient manuscripts held in Timbuktu, but a senior official now says that most of the documents are safe.
France - the former colonial power in Mali - launched a military operation this month after militants appeared to be threatening the south.
Foreign Minister Laurent Fabius said on Wednesday that France intended to leave Mali "quickly", and it was up to African countries to take over.
Several hundred soldiers from West African countries - including Niger and Chad - are already in Mali to help the operation against the militants.
Speaking before a parliamentary committee in Paris, Jean-Yves Le Drian confirmed that the French forces had seized Kidal's airport, according to the AFP news agency.
But the minister said that further progress had been temporarily halted by a sandstorm in the area, about 1,500km (930 miles) north-east of the capital Bamako.
His comments contradicted a report earlier on Wednesday by French army spokesman Col Thierry Burkhard, who said that "French elements were deployed overnight in Kidal".
In addition, Haminy Maiga, interim president of the Kidal regional assembly, told the Associated Press news agency: "The French arrived at 9:30pm [Tuesday] aboard four planes. Afterwards they took the airport and then entered the town and there was no combat.
Kidal was until recently under the control of the Ansar Dine Islamist group, which has strong ties to al-Qaeda in the Islamic Maghreb (AQIM).
The Islamist militants had taken advantage of a military coup in March last year to impose Sharia in a number of cities in the north.
However, the Islamic Movement of Azawad (IMA), which recently split from Ansar Dine, says it is now in charge in Kidal.
The IMA has said it rejects "extremism and terrorism" and wants a peaceful solution.
An IMA spokesman said its leader was in talks with the French military.
Read more of this report from BBC News.