Three Indian soldiers have been killed since Monday as India and Pakistan exchanged cross-border mortar and heavy machine gun fire in their disputed Kashmir region.

District officials In India's western desert state of Rajasthan, said blackout exercises were being held in the border districts at night to prepare civilians ahead of a possible war.

"Entire districts are being blacked out for 15 minutes (at a time) since Tuesday night," one official told the Reuters newsagency. "Sirens are sounded, air force planes will fly over the cities and no power generator sets will be allowed to function."

Tension has risen between the countries since an attack on the Indian parliament on December 13 which left 14 dead.

India has called on Pakistan to suppress two militant groups, Lashkar-e-Taiba and Jaish-e-Mohammad, which it says were behind the attack, and to arrest and extradite their leaders.

Pakistan had first asked for proof, but have now detained Maulana Masood Azhar, leader of the Jaish-e-Mohammad guerrilla group fighting India's rule in the Himalayan region of Kashmir, its only Muslim majority state.

Each of the nuclear rivals justified its military build-up as a response to moves by the other side.

Hard Talk

Indian Prime Minister Atal Behari Vajpayee, speaking on Tuesday before Pakistan's military government said it had detained Maulana Azhar Masood, accused Islamabad of trying force an unwanted war on his country.

"We do not want war but war is being thrust on us and we will have to face it," Vajpayee told a rally organised by the youth wing of his Bharatiya Janata Party on his 77th birthday.

In a public address, Pakistan’s President Pervez Musharraf accused Islamic militants of staining the image of Islam by fuelling extremism But he also used the speech to show his defiance of arch rival India, as the two nuclear powers deploy more troops along their borders.

The neighbours have gone to war three times since independence from Britain in 1947. Twice over Kashmir.

They were on the brink of a fourth war in 1999 after hundreds of armed intruders crossed into Indian-administered Kashmir from Pakistan and were pushed back by an Indian military offensive

US President urges crackdown

The nuclear rivals India and Pakistan are key U.S. allies in the Afghanistan operation.

On Friday, the US president, George Bush, spoke out over the rising tension in the region. He urged Pakistan to crack down on the two militant groups accused of attacking India's parliament. "As President Musharraf does so, he will have our full support," Mr Bush said.