BAMAKO (Reuters) - The United States warned on Monday that northern Mali risked sliding back into war and called for the government and Tuareg separatists to return to talks after deadly weekend clashes in in a traditional rebel stronghold.
The Malian army was preparing to launch an assault on the northern town of Kidal where separatist fighters killed at least eight soldiers and took around 30 civil servants hostage in an attack on the regional governor's office on Saturday.
"The Malian armed forces are at Kidal," Prime Minister Moussa Mara said in a televised address late on Sunday. "We have convinced the head of state that it is highly desirable...that Kidal be totally under the control of the Malian state."
Mali's international partners have been pushing for a final, negotiated settlement to a long cycle of Tuareg independence uprisings, since al Qaeda-linked fighters hijacked a 2012 rebellion and seized the West African nation's desert north.
But the lines between independence fighters and Islamist groups remain blurred. Talks have stalled between the government and groups that split with their erstwhile al Qaeda allies before a French-led military intervention last year.
Mali's U.N. peacekeeping mission MINUSMA said six government workers and two civilians were murdered inside the building during Saturday's assault, which took place during a visit by the prime minister to the northern town of Kidal.
"We are very concerned about what happened and that the response might lead to this region going back into conflict," U.S. Assistant Secretary of State for Africa Linda Thomas-Greenfield told journalists in Paris on Monday.
"It is important for the government to continue to talk to (the MNLA) and work on a reconciliation that will bring them back into the fold."
In an interview on Monday with French radio RFI Mara accused two Tuareg groups - the National Movement for the Liberation of Azawad (MNLA) and the High Council for the Unity of Azawad (HCUA) - of being behind Saturday's attack.
He said they had been supported by Islamist groups, including al Qaeda in the Islamic Maghreb (AQIM).
Kidal is the stronghold of MNLA and while the rebels claimed control of the city on Sunday, they said they had only fought back after coming under a Malian army attack.
MINUSMA called upon both sides on Sunday to refrain from any violence that could endanger civilians in Kidal.
"We are encouraging dialogue as quickly as possible in order to ensure security in Kidal," it said. "For a lasting solution to the problems of the north there is no alternative to a peaceful solution."
While last year's French-led intervention succeeded in driving Islamist groups out of major population centres, Paris pressed Bamako to negotiate with the northern separatists.
France's foreign ministry on Monday condemned the killings of the Malian officials and civilians and called for the immediate release of the remaining hostages held by the rebels.
"The priority is stabilisation," one French diplomat told Reuters. "It's too early to say the whole process has been compromised given it has been tense for a long while already."
France, which currently has some 1,600 troops in Mali, is seeking to reduce its numbers to around 1,000 while deploying 3,000 soldiers elsewhere to tackle the rising threat of Islamic militant groups that have spread across the region since Paris' intervention.
Under a deal last year Mali's government and separatist groups agreed to hold talks over increased autonomy for the north. The rebels were meant to be confined to barracks, but in practice in Kidal they have remained armed and on the streets.
Meanwhile Mali's army had only deployed a small detachment to the town. And with MINUSMA, a 13,000-strong U.N. mission, not yet at full strength, tensions in Kidal have continued to simmer.
Additional reporting by John Irish and Marine Pennetier in Paris and Emma Farge in Dakar; Writing by Joe Bavier; editing by Ralph Boulton