Military spokesmen in Delhi are refusing to give further details until full post-mortems have been carried out, but they have denounced the action as an ''outrageous violation of international conventions''.

Pakistan has not commented on the allegations. But it has said the soldiers were killed in an attack at the border.

The BBC's Mike Wooldridge: The Indian Governmment was taking the matter with the utmost seriousness

India is battling to flush out hundreds of suspected infiltrators in the Himalayas. It says the soldiers were reported missing during a reconnaissance patrol in early May.

The return of the dead soldiers comes a week after India handed over the bodies of three Pakistani soldiers.

Kashmir talks

It is not clear if the incident will affect Saturday's visit by Pakistani Foreign Minister Sartaj Aziz to Delhi for talks aimed at defusing the latest Kashmir crisis.

Times of India East Asia Correspondent Harvey Stockwin:"China is neutral"

Mr Aziz has also unexpectely announced he is making a lightning visit to Beijing on Friday, to find a diplomatic solution to the military escalation. Indian Foreign Minister Jaswant Singh is due to visit China on Monday.

(Click here to see a map of the area)

Despite the imminent discussions, India has intensified its activities in the Kashmir region.

Reports say the Indian Army sent in reinforcements on Thursday. But the Indian Air Force said bad weather had disrupted operations.

On Wednesday, the BBC's Srinagar correspondent reported India's use of Mirage combat aircraft in air attacks.

Medicines are in short supply

India's army chief, General VP Malik, has flown to Kargil with top-level officials, to hold strategy talks with field commanders.

More soldiers are being sent to acclimatise to the harsh mountain conditions, before being moved to higher altitudes for direct combat.

The move comes as India's supply lines to outposts on the Chinese border are coming under attack. Mules are being used to haul howitzer guns while new rocket launchers have been positioned in the area.

International concern

In Germany, the G8 Group of Nations has voiced concern about the situation in Kashmir.

In a statement issued at the end of their summit in Cologne, they called upon India and Pakistan "to respect the Line of Control, to work for an immediate cessation of the fighting and to return to the negotiating table".

The G8 (the US, Russia, Japan, Germany, France, the UK, Canada and Italy) also called on India and Pakistan to sign up to the nuclear test ban treaty.

Emergency supplies

The Indian Army says life-saving drugs and emergency medical supplies are being flown into Srinagar, the capital of Indian-administered Kashmir.

"There is an acute shortage of medicines and beds in the army hospital here," an official was quoted as saying. "Many of the injured are being flown out to hospitals in other cities."