New York — Authorities in Cameroon should investigate reports of journalists being threatened and obstructed from covering the site of an airplane crash on Monday, the Committee to Protect Journalists said today.

"We are alarmed by reports of obstruction and intimidation involving an officer of Cameroon's top elite security unit, the BIR," said CPJ Africa Advocacy Coordinator Mohamed Keita. "We call on authorities to conduct credible investigations and sanction any officers involved."

Officers of the country's top elite security unit, the army's rapid intervention battalion (known as BIR), were working with police at the site of an airplane crash in the northern city of Ngaoundéré, according to local journalists and news reports. The crash, involving a small aircraft flying from Chad to Douala, Cameroon's economic capital, killed one passenger and left four others injured, Agence France-Presse reported.

Officers at the scene threatened and obstructed journalists working for private news outlets, but allowed local officials and reporters for the state-controlled national public broadcaster Cameroon Radio and Television to gain access to the site, according to the National Syndicate of Cameroonian Journalists and CPJ interviews.

Salomon Kankili, a reporter for the independent paper Le Messager, told CPJ that a BIR officer grabbed him by the neck and threw him on the ground after he asked about the basis for the restrictions. The same officer threatened unspecified reprisals against Kankili and another reporter, Adolarc Lamissia of the daily Le Jour, if they published anything about him, the syndicate and Le Messager reported.

Joseph Mouafo, a reporter for the private broadcaster Camnews24, told CPJ that the same BIR officer threatened to break his video camera if he filmed the crash site, even from a distance. Mouafo and another TV reporter, Clevis Moussa of Equinoxe, both left after being chased away, he said.

Lt. Pioka, the regional commander of BIR, did not immediately respond to CPJ's telephone and text messages.

The BIR operates under the authority of the Ministry of Defense with a mandate to combat criminality and general insecurity in border regions, but it has also intervened in political protests, according to CPJ research. Local press has reported allegations of shootings, assaults, harassment and even murders of civilians by BIR officers. In 2010, at least 16 officers had been expelled for misconduct, according to news reports.

The office of Cameroon's Ministry of Defense said it would investigate the reports of threats and obstruction. Both Abakar Ahamat, the regional governor, and Col. Guy Beyegue, head of the paramilitary police corps, denied issuing any orders to restrict the press from reporting.