French President Francois Hollande said the “terrorist groups, drug traffickers and extremists” in northern Mali “show a brutality that threatens us all.” He vowed that the operation would last “as long as necessary.”

France said it was taking the action in Mali at the request of President Dioncounda Traore, who declared a state of emergency because of the militants’ advance.

The arrival of the French troops in their former colony came a day after the Islamists moved the closest yet toward territory still under government control and fought the Malian military for the first time in months, seizing the strategic city of Konna.

Sanda Abou Moahmed, a spokesman for the Ansar Dine group, condemned Mali’s president for seeking military help from its former colonizer.

“While Dioncounda Traore asked for help from France, we ask for guidance from Allah and from other Muslims in our sub-region because this war has become a war against the crusaders,” he said by telephone from Timbuktu.

For the past nine months, the Islamic militants have controlled a large swath of northern Mali, a lawless desert region where kidnapping has flourished.

“French armed forces supported Malian units this afternoon to fight against terrorist elements,” Hollande said in Paris.

He did not give any details of the operation, other than to say that it was aimed in part at protecting the 6,000 French citizens in Mali, where seven of them already are being held captive.

French Foreign Minister Laurent Fabius, when asked whether France had launched airstrikes, said, “To the question of whether there was an air intervention, the response is yes.” He refused to give any other details for security reasons.

France is operating helicopter gunships in Mali, two diplomats told The Associated Press. They spoke on condition of anonymity because they were not authorized to discuss the operation publicly. French special forces, who have been operating in the region recently, are also believed to be taking part in the military operation, one diplomat said.

U.N. Secretary-General Ban Ki-moon told the AP that Senegal and Nigeria also responded to an appeal from Mali’s president for help to counter the militants.

Residents in central Mali said they had seen Western military personnel arriving in the area, with planes landing at a nearby airport throughout the night.

Col. Abdrahmane Baby, a military operations adviser for the foreign affairs ministry, confirmed in the Malian capital of Bamako that French forces had arrived in the country but gave no details.

“They are here to assist the Malian army,” he told reporters.

Traore went on national television Friday night to declare the state of emergency, saying it would remain in effect for 10 days and could be renewed.

“The situation on the front is over all under control,” he said.

Traore called on mining companies and nongovernment organizations to turn their trucks over to Malian military, raising questions about the army’s ability.

State Department spokeswoman Victoria Nuland said the U.S. was “deeply concerned” by events in Mali, and that Washington was closely consulting with Paris. She said neither France nor Mali has asked for U.S. military assistance.

France has led a diplomatic push for international action in northern Mali but efforts to get an African-led force together, or to train the weak Malian army, have dragged.

The French quickly mobilized after the Islamists seized the city of Konna on Thursday, pushing closer to the army’s major base in central Mali. Late Friday, Malian Lt. Col. Diarran Kone said the government had not been able to recapture the town.

The United Nations Security Council has condemned the capture of Konna and urged U.N. member states to assist Mali “in order to reduce the threat posed by terrorist organizations and associated groups.”

Late last year, the 15 nations in West Africa, including Mali, agreed on a proposal for the military to take back the north, and sought backing from the U.N.

The Security Council authorized the intervention but imposed certain conditions. Those include the training of Mali’s military, which has been accused of serious human rights abuses since a military coup last year sent the nation into disarray.

The fighting Wednesday and Thursday for Konna represents the first clashes between Malian government forces and the Islamists in nearly a year, since the militants seized the northern cities of Gao, Kidal and Timbuktu.

The Islamists seized the town of Douentza four months ago after brief standoff with a local militia, but pushed no farther until clashes broke out late Wednesday in Konna, a city of 50,000 people, where fearful residents cowered inside their homes. Konna is just 45 miles (70 kilometers) north of the government-held town of Mopti, a strategic port city along the Niger River.

A soldier, who spoke on condition of anonymity because he was not authorized to speak to journalists, acknowledged that the army had retreated from Konna. He said several soldiers were killed and wounded, though he did not have precise casualty figures.

Al-Qaida’s affiliate in Africa has been a shadowy presence for years in the forests and deserts of Mali, a country hobbled by poverty and a relentless cycle of hunger. Most Malians adhere to a moderate form of Islam.

In recent months, however, the terrorist group and its allies have taken advantage of political instability, taking territory they are using to stock weapons and train forces.

Turbaned fighters control major towns in the north, carrying out amputations in public squares just as the Taliban did. And like in Afghanistan, they are flogging women for not covering up. Since taking control of Timbuktu, they have destroyed seven of the 16 mausoleums listed as world heritage sites.

French Foreign Minister Laurent Fabius said his government was taking action because “in recent days, the situation unfortunately deteriorated very seriously.”

The delay by the international community in taking action allowed “the terrorist and criminal groups of northern Mali … to move toward the south with the goal of … installing a terrorist state.”

The Islamists insist they want to impose Shariah only in northern Mali, though there long have been fears they could push farther south. Bamako, the capital, is 435 miles (700 kilometers) from Islamist-held territory.

Hollande said the French government will address parliament on Monday about the operation.

The intervention earned quick, widespread support from leading voices inside France across the political spectrum. Even far right leader Marine Le Pen — one of the many critics of the unpopular Hollande — called the Socialist leader’s action “legitimate.”

France has hundreds of troops across western Africa, with bases or sites in places such as Senegal, Ivory Coast, Chad and Gabon. However, Hollande has said that he wants to create a new relationship with former colonies in Africa.

The operation in Mali is the first military intervention under his leadership, and comes just weeks after he pulled out France’s last combat troops out of Afghanistan, ending an increasingly unpopular 11-year presence there.

France was a leading force in the NATO operation against Libyan dictator Moammar Gadhafi’s forces in 2011. Also that year, France played a driving role in an international military intervention to oust Ivory Coast’s Laurent Gbagbo, who refused to leave power after disputed elections. Both of those operations were under Hollande’s predecessor, Nicolas Sarkozy.