The second-largest rebel group in the Democratic Republic of Congo has arrested one of its officers suspected of killing civilians.

More arrests are expected in connection with human rights abuse in eastern Congo, the leader of the Movement for the Liberation of Congo (MLC), Jean-Pierre Bemba, said.

But Mr Bemba rejected claims that his men had been involved in acts of cannibalism.

People fleeing recent fighting near the north-eastern town of Beni, in Ituri province, have accused the soldiers of rape, arbitrary execution and cannibalism.

More than 100,000 people have been displaced by fighting between rival rebel factions in the region.

'Disciplined'

The officer was arrested as a result of an investigation into the execution of four civilians in Mambasa and widespread abuse against locals.

Lt-Col Freddy Ngalimo led the rebel forces who fought government troops in Ituri in October last year.

Mr Bemba said that more arrests could be expected.

"There will be other arrests in the days to come among rebel elements who are in Mambasa today," he told the French news agency, AFP.

Mr Bemba says his men are not cannibals

He said he had invited Human Rights Watch and Amnesty International to visit the area to investigate any abuse committed during the recent fighting.

But the MLC denies reports that its men have committed acts of cannibalism.

"I don't believe it," the secretary general of the movement, Olivier Kamitatu, told the BBC's Network Africa programme.

"MLC troops are quite disciplined. I want an independent commission and if exactions have occurred, if the MLC is responsible, then we will investigate and punish," he said.

'Appalling'

On Monday, DR Congo President Joseph Kabila condemned the crimes committed in Ituri.

"The grave human rights violations committed in the region cannot be endured, or go unpunished," he said.

This woman's husband and two daughters have been killed by soldiers

"The crimes committed in Ituri cannot be camouflaged as acts of war, and it is impossible to imagine that justice will be done," he said during talks with the UN special representative in the DRC, Amos Namanga Ngongi.

The UN high Commissioner for human rights, Sergio Vieira de Mello, said on Monday that the crimes committed in Ituri were "appalling".

"They show a total absence of state structures in that part of the country as well as anarchy, which have led to horrifying results, such as rape, gratuitous - or even deliberate - violence, including cannibalism," he told the BBC's French service.

Mr de Mello said he was consulting UN and government officials in Kinshasa with a view to taking measures to put an end to crimes in eastern Congo.