* Separatist rebels said Nov. 29 they were ending ceasefire
* Plume of black smoke hangs over Kidal
* Some al Qaeda-linked fighters still in northern Mali
BAMAKO, Dec 14 (Reuters) - A car bomb destroyed the only operating bank in the northern Malian town of Kidal on Saturday, witnesses and military sources said, two weeks after separatist Tuareg rebels said they were ending a ceasefire with the government.
There was no word from the authorites or sources on casualties and no immediate claim of responsibility for the attack on the Malian Solidarity Bank, which took place at around 0645 local time (0645 GMT).
Some fighters linked to al Qaeda are still holding out in the north nearly a year after the start of a French offensive aiming to drive them from the desert region they occupied for most of 2012 after hijacking a Tuareg separatist rebellion.
"The bank is no more," said a soldier contacted by telephone. The building was being protected by the Malian army and the U.N. peacekeeping mission in Mali known as MINUSMA.
"A vehicle in front of the bank is in flames after the explosion. There is a huge amount of bank smoke in the sky hanging over the town," resident Ibrahim Maïga said. Another resident, Youssouf Touré, said the bank was reduced to rubble.
The rebels, who demand an independent homeland they call Azawad, ended a five-month ceasefire on Nov. 29, a day after Malian troops clashed with stone-throwing protesters who blocked a visit by the prime minister to Kidal.
The French-led offensive scattered Islamists across Mali and into neighbouring countries but the groups have stepped up operations in recent months, attacking U.N. peacekeepers and killing two French journalists in Kidal last month.
The Tuaregs seized control of Kidal after the French offensive had driven Islamists out of the town, leading to tensions with the government in Bamako.
Under a June peace pact that allowed the army to return to Kidal, rebels are still inside the town but are required to return to their barracks under the supervision of U.N. peacekeepers, stop carrying arms in public and dismantle all roadblocks.