Mali's Prime Minister Moussa Mara said Sunday the country was "at war" with terrorists in the northern city of Kidal after clashes between separatist militants and the Malian army left 36 dead.
Eight soldiers and 28 insurgents were killed in fighting on Saturday outside the regional governor's offices during a visit by Mara to the desert town, the government said, adding that around 30 civil servants were being held hostage.
"The terrorists have declared war on Mali, so Mali is at war against these terrorists. We will mobilise the resources to fight this war," Mara told AFP by telephone.
Kidal, 1,500 kilometres (900 miles) northeast of the capital Bamako, was the scene of anti-government protests by several hundred people on Friday and Saturday who demonstrated at the regional airport against the visit.
Mara's predecessor Oumar Tatam Ly was forced to cancel a trip in November to Kidal -- the stronghold of Mali's Tuareg separatist movement -- after protesters occupied a runway at the airport.
"When someone attacks the republic, he is a terrorist, whatever his origin, or allegiance to a territory. We will take a war without mercy to these terrorists," Mara added.
"Our forces are motivated. We will provide them with what they need to win total victory."
Mara is on his first tour of the north since his appointment in April.
He visited the desert caravan town of Timbuktu on Friday, Kidal on Saturday and arrived on Sunday in Gao, northern Mali's largest city.
Security is being provided by the United Nations' MINUSMA peacekeeping force and soldiers from Operation Serval, the French-led military mission against Islamist militants in northern Mali.
It was not immediately clear if the French troops had been involved in events in Kidal over the weekend.
"The prime minister left Kidal this morning with his delegation by helicopter... it is calm at the moment," a MINUSMA official told AFP.
The force said in a statement on Saturday it "strongly condemns these acts of violence".
"Such developments are counterproductive and contrary to the will of the people of Mali, who aspire to peace and lasting stability," the statement added.
MINUSMA said on Saturday 19 of its police and seven protesters had been wounded in clashes at the airport since the demonstrations began, though none seriously.
Malian Defence Minister Soumeylou Boubeye Maiga announced reinforcements in Kidal, identifying the rebels as members of the Tuareg separatist National Movement for the Liberation of Azawad who were "supported by members of terrorist groups".
"During the clashes, the Malian armed forces have recorded eight dead and 25 injured, and 28 killed and 62 wounded were counted on the side of the aggressors," he said. "Our forces have taken control of all government buildings except, for the moment, the governor's offices, where the MNLA and terrorists are holding 30 officials hostage," he said.
Maiga said the army would "strengthen their positions quite quickly in Kidal and its surroundings to secure people and property", adding that troop numbers would be doubled, if necessary.
The MNLA evacuated the governor's offices in November last year after a nine-month occupation.
The move was in line with the terms of a June peace deal, which paved the way for presidential elections across the country.
But the process deeply divided the MNLA, whose ultimate goal is the independence of Azawad, the minority Tuareg name for their homeland in northern Mali.
Up until the agreement, the MNLA had refused to allow any government soldiers or civil servants into the desert town.
The election -- won by Ibrahim Boubacar Keita in August last year -- was seen as a key step to restoring stability in Mali.
The country descended into crisis in January 2012, when the MNLA launched the latest in a string of Tuareg insurgencies in the north.
A subsequent coup in Bamako led to chaos, and armed Islamist radicals linked to Al-Qaeda overpowered the Tuareg to seize control of Mali's northern half.
A French-led military operation launched in January 2013 ousted the extremists, but sporadic attacks have continued, and the Tuareg demand for autonomy has not been resolved.