BANGUI (Reuters) - The rebel leader who seized power in Central African Republic, Michel Djotodia, was elected president on Saturday by an acting parliament.

Djotodia led thousands of rebel fighters from the Seleka coalition into the riverside capital of the mineral-rich country on March 24, toppling President Francois Bozize.

African heads of state and Western powers had refused to recognize him as the country's legitimate leader and called for the creation of the transitional council to lead the nation to elections within 18 months.

The 105-member transitional council, meeting in parliament in Bangui on Saturday, confirmed Djotodia, the only candidate, by acclamation - paving the way for recognition.

Djotodia has agreed not to seek re-election at the end of the transition.

"I will do as you instruct me to do, and not according to my wishes," Djotodia told the delegates of the council, selected by consensus from political parties and civil society organizations.

Djotodia said the worsening security in the ramshackle capital and across the impoverished nation would be his main concern during the transition period.

International aid organizations have said uncontrolled armed groups including members of the Seleka movement continue to loot, spread chaos and recruit children into their ranks.

"The new Seleka government should assume their responsibility and re-establish control over these armed groups," French aid organization MSF said in a statement.

Seleka, a grouping of five rebel movements, launched its insurgency in early December, accusing former president Bozize of reneging on a 2007 peace deal.

The insurgents came close to capturing the capital before accepting another peace deal in January under which some of their leaders joined the central government.

But they relauched their offensive and seized the capital in March, accusing Bozize of not respecting the deal.

(Reporting by Paul Marin Ngoupana; Writing by Bate Felix; Editing by Alison Williams)