Malian security forces on Saturday stormed a hotel used by United Nations staff and freed four hostages held there by suspected Islamist militants during a nearly 24-hour siege in which 12 people died.

The gunmen had seized the Byblos Hotel in the town of Sevare, around 600 km (400 miles) northeast of the west African nation's capital Bamako, early on Friday and held off troops who quickly surrounded the building.

The attack, far to the south of the Islamist militants' traditional desert strongholds, was the latest in what appears to be a growing campaign against Malian troops and U.N. personnel by remnants of an al Qaeda-linked insurgency.

"(The siege) seems to be over and it has ended well," said a Malian defence ministry spokesman, Colonel Diaran Koné. "We freed the four hostages. But unfortunately we also found three bodies at the site."

A spokeswoman for Mali's U.N. peacekeeping mission, MINUSMA, said four U.N. contractors - two from South Africa along with a Russian and a Ukrainian - had been freed in the pre-dawn raid by security forces.

"At no point were they discovered by the terrorists in the hotel. They were hiding," Radhia Achouri said, adding that the mission was verifying whether any other MINUSMA personnel were present inside the hotel.

Three hostages died during the ordeal, Malian government spokesman Choguel Kokala Maiga said, adding that authorities were still attempting to confirm their nationalities.

Five soldiers and four gunmen, including one who officials earlier said was strapped with explosives, were also killed, he said.

Seven suspects have been arrested in connection with the attack, according to a government statement released late on Friday.

Ukraine and Russia had previously confirmed that their citizens were among the hostages. Russian news agencies, citing a press attache at Moscow's embassy in Mali, said a Russian hostage employed by the airline UTair was among those freed on Saturday.

At least one French national was also believed to have been staying at the hotel, Malian military officials said on Friday.

A French foreign ministry official said Paris was attempting on Saturday to verify whether any of its citizens had been among the hostages.

Small Arms Fire

A 2013 French-led military operation drove back Islamist fighters, who had taken advantage of an ethnic Tuareg rebellion and a military coup to seize territory in the north a year earlier.

While the United Nations has managed to broker a tenuous peace agreement between the government and Tuareg separatists, Islamist fighters left out of the negotiations have mounted a insurgency.

Former colonial ruler France and other Western and regional nations fear Islamist fighters could turn the remote region into a launch pad for attacks further afield if they regain power there.

Describing the security forces' operation early on Saturday, a Sevare resident living near the hotel told Reuters: "The assault ... took place between 4 and 5 o'clock this morning (0400-0500 GMT). We didn't hear heavy weapons this time. There was just some small arms fire."

On Friday Malian forces had used heavy weapons, including rocket-propelled grenades, in a failed attempt to dislodge the gunmen that then gave way to the prolonged stand-off.

The resident and a Malian military source said a special unit of the Malian gendarmes had carried out Saturday's pre-dawn raid.

Koné, the defence ministry spokesman, said that French forces had backed the operation. But a French army spokesman said French soldiers had not been directly involved in the assault on the hotel.

"We played a coordination role with MINUSMA and the Malian armed forces, but this is a normal role that we play all the time," the official said.