Counter battery radar

The radar can pinpoint the location of mortars, artillery and rocket launchers from a distance of about 300 kilometres, after tracking a shell for only a few seconds, and direct return fire.

The Defense Department notified Congress on Wednesday that India had requested four more "Firefinder" AN/TPQ-37 counter-battery radar units plus support equipment.

After the initial deal in April, the Pentagon said the sale would not affect the military balance with Pakistan, which deploys the AN/TPQ-36, an earlier version of the Firefinder radar.

India, which has fought three border wars with Pakistan since independence from Britain in 1947, and one with China in 1962, has traditionally bought Russian and British military equipment.

India unveiled a massive increase in its defence budget earlier this year as tensions with Pakistan over Kashmir escalated.

The US lifted restrictions on military sales to India and Pakistan, imposed after their tit-for-tat nuclear tests in 1998, at the start of 2002.

Military ties

The Defense Security Cooperation Agency, which handles US government-to-government weapons sales, said the deal could be worth an additional $100m on top of the $146m initial deal.

It was announced during a visit by Indian Prime Minister Atal Behari Vajpayee to the US.

"Security issues have cast a shadow on our relationship. I believe this is unnecessary. We have much in common and no clash of interests," Mr Vajpayee said in a speech to a joint session of the US Congress.

The Pentagon agency said the proposed sale "will contribute to the foreign policy and national security of the US by helping to improve the security of a friendly country which has been, and continues to be, an important force for political stability and economic progress in South Asia."

Congress has 30 days to reject the arms deal but no proposal by the Defence Department for a foreign sale has ever been barred.

Last Friday, the US Army placed the order for the original eight radar units with Thales-Raytheon Systems, a joint venture of France's Thales and Raytheon of the US.

A company spokeswoman said they were destined for India.