Just a month ahead of Defence Minister A K Antony's crucial visit to Russia [Images] to sort out the issue of price for warship Admiral Groshkov and Sukhoi fighters, New Delhi and Moscow [Images] have engaged in another spat over supply of equipment for maritime spy planes.

India has refused to accept further deliveries of upgraded IL-38 anti-submarine aircraft complaning that the plane-detection equipment is not working to specifications.

"The upgraded maritime aircraft are not working to specified parameters in Indian conditions," top navy sources said in Delhi.

India has gone for upgradation of its fleet of five IL-38 aircraft to fill the gap in its maritime reconnaissance capability and has received two upgraded aircraft from Russia.

The delivered aircraft are leaving gaps in its target acquisition and fire control suits, the sources said.

The navy's evaluation came as reports from Moscow quoted the chief executive officer of the ILyushin Aviation Complex Viktor Livanov as charging that "Indian Navy was hindering the implmentation of the contract by putting forward unjustified technical requirements."