* Mali rebels seen linked to Nigeria's Boko Haram
* Nigeria deploys 1,200 troops to Mali conflict
* President says Nigeria needs to show leadership (Adds quotes throughout, background on Boko Haram)
By Emma Farge
GENEVA, Jan 22 (Reuters) - Nigerian President Goodluck Jonathan said on Tuesday his country's troops would stay in Mali to back military operations against al Qaeda-linked rebels until the crisis was resolved.
Nigeria plans to deploy up to 1,200 troops as part of a West African intervention force to support French and Malian troops battling Islamist militants in the Sahara desert.
Allied French and West African forces are seeking to drive the rebels out of northern Mali, which they seized from government forces after a coup last year left a power vacuum.
"We cannot pull out until we have solved the problem. I cannot tell you when we will solve the problem, but Nigeria is totally committed and we remain committed until the crisis is resolved," Jonathan told Reuters in an interview in Geneva.
"Until democratically elected people take over the government of Mali, we will not pull back."
As well as deploying troops, Nigeria also has warplanes in neighbouring Niger ready for missions in Mali.
The hostage crisis at an Algerian gas plant shortly after the French intervention has raised fears among other West African countries of a backlash from Islamists at home.
Jonathan said Nigeria had a direct interest in intervening in Mali, pointing out links between the Nigerian Islamist sect Boko Haram and al Qaeda's north African wing in Mali.
"We believe that if we stabilise northern Mali, not just Nigeria but other countries that are facing threats will be stabilised," he said.
"Nigeria controls 55 percent of the economy of West Africa and Mali is a West African country so we expect the Nigerian contribution to take that proportion. If we don't show that leadership other countries may not come up strong."
Boko Haram killed hundreds of people last year in a campaign to impose sharia (Islamic law) on religiously mixed Nigeria. Its deadliest single attack was in Kano last January when attacks on multiple police stations killed 186 people, most of them civilians.
On Tuesday Islamic gunmen fired on residents in a market town of northeast Nigeria, killing at least 18 people in the most deadly attack in weeks. It was not immediately clear if Boko Haram had played a role.
Asked if there was a possibility that the leader of Boko Haram, Abubakar Shekau, was fighting in Mali, Jonathan said only that it was possible. "They have no boundaries. They don't respect international boundaries. Today they are in Mali and in Niger tomorrow then Cameroon and Mali," he said.
France, which launched air strikes in Mali 11 days ago to stop a surprise Islamist push towards the capital Bamako, has urged a swift deployment of the U.N.-mandated African force to back up its 2,150-strong ground forces already there.
Chad became the latest country to join the effort on Tuesday, sending an armoured column of troops to Nigeria, to deploy along the Malian border. (Additional reporting by Tim Cocks; Editing by Mark Heinrich)