Arriving in Paris after fleeing from Chad via neighbouring Cameroon, parliamentarian Ngarlejy Yorongar said he believed fellow opposition leader Ibn Oumar Mahamat Saleh had been killed after he was detained by soldiers just over a month ago.

"Ibn Mahamat Saleh arrived after me. The soldiers who brought him started punching him, pistol-whipping him, kicking him," Yorongar told French radio station RFI shortly after arriving at Charles de Gaulle airport in Paris.

"They took him to a cell and between (February) the 4th and 6th I believe he was killed, unless there was a miracle, but I don't believe there was. ... Given the state they left him in, in my opinion he's dead," he said.

Yorongar, Saleh and former President Lol Mahamat Choua -- all key opposition figures -- disappeared on Feb. 3 as government forces fought to re-establish control of N'Djamena after opposition forces opposed to President Idriss Deby.

Deby's government has said it is holding Choua under house arrest as a "prisoner of war". Saleh has still not appeared, and Deby has said he does not know here he is.

France, the European Union and international human rights groups called on Deby to clarify the whereabouts of the opposition figures.

During a brief visit to Chad by French President Nicolas Sarkozy last week, Deby announced an investigation was being opened into what happened to them.

Yorongar told reporters he had come to France for medical tests because he feared he had been poisoned while in captivity.

He said he was beaten on the day of his abduction and was held for 18 days at a secret location before being released and fleeing to Cameroon where the French embassy gave him a visa.

Asked if he would seek political asylum in France, Yorongar said: "Now is not the time."

More than 400 civilians were killed or disappeared in two days of confused street battles in N'Djamena during the battle, before the opposition forces retreated towards eastern Chad's border with Sudan.

Chad's opposition forces have strongly criticised French support for Deby's government. Paris has insisted it did not provide direct military assistance during the fighting in N'Djamena but has said it did help resupply the Chadian army.

Agencies