By Sebastian Moffett

LUXEMBOURG (Reuters) - The European Union said on Monday it would draw up plans for a possible military training mission to help Mali's army regain control of the Islamist-dominated north of the country.

Mali descended into chaos in March when soldiers toppled the president, leaving a power vacuum that enabled Tuareg rebels to seize two-thirds of the country. But Islamists, some allied with al Qaeda, have hijacked the revolt in the north.

"We believe there's a real risk for the region if Mali remains an ungoverned space, free for terrorists and drug traffickers to operate," said EU foreign affairs chief Catherine Ashton.

"I hope that what we'll see in the future is a Malian government with a credible roadmap for the restoration of democratic government."

Announcing humanitarian and other measures to help Mali, the bloc said it would in particular consider ways to retrain the Malian defense forces, and develop plans for an eventual military mission.

The decision was taken at a meeting of EU foreign ministers in Luxembourg, where they called for such a plan to be drawn up for their next meeting on November 19.

The EU move followed Friday's U.N. Security Council urging African regional groups and the United Nations to present within 45 days a specific plan for military intervention in Mali to help government troops reclaim the north of the country.

The 15-nation council unanimously passed a French-drafted resolution to try to revive stalled attempts to deal with the crisis, which it warned could destabilize the Sahel, a belt of land with nearly a dozen of the world's poorest countries on the southern rim of the Sahara.

Al Qaeda-linked Islamists from the MUJWA group threatened on Saturday to "open the doors of hell" for French citizens if France kept pushing for armed intervention to retake the north.

Some EU ministers fear Mali could turn into a breeding ground for militancy, who could attack Europe.

"We have to avoid at an early stage the development of a second Somalia, without any rule of law," said German Foreign Minister Guido Westerwelle. "Because then there are going to be founded further terrorist schools that will endanger our situation here in Europe too."

The European Union is considering a range of options for an eventual military operation, according to one Western diplomat. These range from dispatching 150 or so military trainers to Mali, to sending up to 500 soldiers who would not only train Malian troops but might also accompany them in battle.

The U.N. Security Council said it would be ready to consider a second resolution to approve military intervention in Mali after a detailed plan is received from the West African regional body ECOWAS, the African Union and the United Nations.

The African Union, ECOWAS, the United Nations and others were due to meet in Bamako on October 19 to discuss the way forward. ECOWAS has intervened militarily in past African conflicts, including the wars in Liberia and Sierra Leone.

(Additional reporting by Angelika Stricker; Editing by Alison Williams)