RABAT - US troops are to redeploy from Morocco after Rabat cancelled annual war games in the kingdom, the US army said Wednesday, amid sharp disagreement over plans for a UN mission in Western Sahara.

The "African Lion 2013" joint military exercises, which began last week and would have run to April 27, were to involve 1,400 personnel from US Africa Command (Africom) as well as 900 members of the Moroccan armed forces.

Their cancellation comes as US-backed plans emerged on broadening the mandate of the UN peacekeeping mission in the disputed Western Sahara region to probe human rights abuses, an initiative categorically rejected by Morocco.

"We're readying those troops for redeployment to where they came from sooner than we had planned for," Africom spokesman Chuck Prichard said.

"The exercises have been deferred at the request of the kingdom of Morocco," and no new date had been set for them to resume.

"As far as the reasons why, the Moroccan officials made those decisions. I'd have to refer you to them," he added.

On Tuesday evening, the Moroccan government spokesman declined to comment on reports the military exercises had been cancelled.

But he called plans to alter the mandate of the UN peacekeeping mission in Western Sahara, officially known as MINURSO, an attack on Morocco's sovereignty that would have "harmful consequences" for regional stability.

The war games, which were to take place throughout Morocco, and were geared to building "military partner-nation capacity," involved amphibious and peacekeeping operations, aerial refuelling and low-level flight training.

Armed forces from some 13 European and African countries had also been due to take part, according to Africom, the branch of the US military responsible for its Africa operations.

Washington is expected to present to the 15-nation UN Security Council at the end of April its proposal that MINURSO's mandate be extended to monitor rights abuses, according to diplomatic sources.

The initiative has set off a furious lobbying campaign by Morocco, which began annexing the former Spanish colony in 1975 in a move not recognised by the international community.