BAMAKO, Mali — France claimed new successes in its campaign to oust Islamist extremists from northern Mali on Sunday, bombarding the major city of Gao with airstrikes targeting the airport and training camps used by the al-Qaida-linked rebel group controlling the city.

France’s foreign minister also said the 3-day-old intervention is gaining international support, with communications and transport help from the United States and backing from Britain, Denmark and other European countries.

The French-led effort to take back Mali’s north from the extremists occupying it has included airstrikes by jets and combat helicopters on at least four northern towns, of which Gao is the largest. Some 400 French troops have been deployed to the country in the all-out effort to win back the territory from the well-armed rebels, who seized control of an area larger than France itself following a coup in Mali nine months ago.

“French fighter jets have identified and destroyed this Sunday, Jan. 13, numerous targets in northern Mali near Gao, in particular training camps, infrastructure and logistical depots which served as bases for terrorist groups,” the French Defense Ministry said in a statement.

Residents of Gao confirmed that the targets included the city’s airport, as well as the building that served as the base for the town’s feared Islamist police, which — in their adherence to a strict version of Muslim law — have carried out numerous punishments including amputating limbs of accused thieves. 

But the intervention has come with a human cost in the city of Konna, the first to be bombed on Friday and Saturday. The town’s mayor said that at least 10 civilians were killed, including three children who threw themselves into a river and drowned trying to avoid the falling bombs.

French President Francois Hollande authorized the military operation, code-named “Serval” after a sub-Saharan wildcat, after it became clear that the advancing rebels could push past the defenses in the town of Mopti, the first town on the government-controlled side, which has the largest concentration of Malian soldiers.

The decision catapulted the world and Mali’s neighbors into a military operation that diplomats had earlier said would not take place until at least September. France’s defense minister said they had no choice because of the swift rebel advance.

On Saturday, the body representing nations in West Africa announced that the member states would send hundreds of troops of their own, including at least 500 each from Niger, Burkina Faso and Senegal, as well as from Nigeria.

U.S. officials have said they had offered to send drones to Mali and were considering a broad range of options for assistance, including information-sharing and possibly allowing limited use of refueling tankers. British Prime Minister David Cameron also agreed to send aircraft to help transport troops.