Royal Navy Sea Harriers from the aircraft carrier HMS Invincible, stationed in the Adriatic, are searching the skies over Kosovo for Yugoslavia's prized fleet of MiG jets.

The Yugoslav air force has kept its Russian-built MiG 29s under wraps, preferring to sacrifice the less valuable MiG 21s.

The MiG 29s have mainly stayed in their hangars, breaking cover only occasionally to dash from one airfield to another.

The Serb pilots do not have night vision equipment and have chosen to manouvre at dusk, when Nato pilots have difficulty spotting them.

'Frightened of Nato firepower'

One pilot from the Royal Navy's 800 Squadron, who declined to be named for security reasons, said the Yugoslavs appeared scared to take on Nato.

MiG 29s: Rarely in the skies over Kosovo

The 29-year-old said: "From what we have seen of the times when they have been shot down, the MiGs have just flown in a straight line."

He said it was not sure whether their lack of evasive action was due to "pilot inexperience or ineffective radar".

Eight of the 14 MiG 29s the Yugoslav air force had at the beginning of the conflict are understood to have been destroyed.

But the Sea Harriers have not been able to claim credit for any of the "kills".

'Shoot something down'

The pilot said it was a frustrating time and added: "Without being warmongering, we are here to do a role and it would be good for the squadron to say that we have shot someone down."

The guided missile destroyer HMS Newcastle is providing the Invincible with anti-missile cover.

Armed Forces Minister Doug Henderson visited the Invincible and Newcastle during a three-day tour of British forces involved in he Nato operation against Yugoslavia.

Mr Henderson also visited the nuclear submarine HMS Splendid, which has been launching Tomahawk cruise missiles at Serbian targets.

He said: "Morale is very high because they know that what we are doing here is important and just."