By BBC correspondent Lara Pawson in Luanda

The Angolan rebel group, Unita, says it shot down a cargo plane which crash-landed in north-east Angola on Wednesday.

The five people who were on board the plane are reportedly alive and well. However there are growing fears for their safety.

The company licensed to operate the plane, Savan Air, is appealing to the United Nations for assistance.

It believes that the three crew members and two passengers are being held by Unita.

So many aircraft have fallen out of Angolan skies during the past six months, the latest incident hardly makes headline news in the capital, Luanda.

The Russian-built Antonov 12 was carrying a cargo of chickens 700 km east of Luanda to Saurimo when it was forced to make an emergency landing.

Savan Air originally thought the plane had landed in government-held territory after the pilot had experienced technical problems. But claims by Unita that they are responsible for downing the aircraft have sent Savan Air into panic.

Less than two months ago, another Russian cargo plane made an emergency landing in the same area. A few days after the incident, Unita claimed it had hit the aircraft and taken hostage the three Russian crew members.

There has been no news on the fate of the three hostages since and whether the plane was actually shot down has never been proved.

Doubt over claims

Several analysts of Angola have cast doubt over the plausibility of Unita's claim.

One military expert in Luanda argues that the rebels use these unfortunate incidents to their own advantage to spread fear and create a sense of their apparent omnipotence.

Many of the Russian planes used in Angola are extremely old, badly maintained and - according to one South African pilot - unfit for flying.

Unita knows that few airline companies will send investigation teams to the site of the crash. Because of the war, the risks are simply too high.