By Mike Wooldridge BBC World Affairs correspondent

India and Pakistan, both supposedly on the same side in the US-led "war on terror", had hundreds of thousands of troops deployed in a tense border stand-off. It continues to this day, even if the tension is lower.

The confrontation is between two nuclear-capable nations that are home to one sixth of the world's population between them. It has caused as much alarm around the world as the continuing violence in the Middle East or any other trouble spots - possibly even more to judge by the amount of diplomatic effort invested in urging restraint on both Delhi and Islamabad.

Nurtured

India and Pakistan have fought three outright wars since independence from Britain in 1947. And only three years ago there was a limited war between them in the Kargil region of Kashmir which added hundreds more to the total of those who have died in the various conflicts. But the attacks of 11 September brought a new dimension to it all.

Until then Pakistan had been the main ally of the Taleban regime. The Taleban had been nurtured with Pakistani support.

In the aftermath of the New York and Washington attacks, George Bush issued his warning to countries like Pakistan - you are with us, or against us.

Pakistan did a U-turn. Its leader, General Musharraf, decided to provide the American-led coalition with logistical support for the bombing campaign in Afghanistan. He knew he risked a backlash, and for a time there were protests in Pakistani towns and cities.

India was wary. It has always accused Pakistan of giving military support to those involved in the separatist campaign in India's only Muslim-majority state, Kashmir.

It suspected that there could be a trade-off in Pakistan abandoning the Taleban - that the price India might have to pay was a stepping up of the pressure in Kashmir.

Major attack

Two devastating attacks in quick succession on the assembly in Srinagar, Kashmir's summer capital, and at the parliament building in Delhi seemed to India to bear out its fears. The build-up of troops on the border followed. And so, too, did the first wave of diplomatic shuttling.

When General Musharraf announced a crackdown on militancy in January the international community urged India to give Pakistan the benefit of the doubt.

For a time the gruesome sectarian violence in the Indian state of Gujarat overshadowed the crisis on the border. But then there was a major attack on army families in Kashmir.

Western governments became increasingly explicit in their demands that Pakistan stop what they called cross-border terrorism

India protested that it could see little evidence of General Musharraf reigning in the militants, and the tension between the two countries rose again.

India's case was that it was engaged in a war on terror on its doorstep and the world was not putting enough pressure on General Musharraf.

Pakistan continued to argue that the root of the tension was India denying the people of Kashmir the right to decide their own future - and the international community should be putting the pressure on India.

Testing time

General Musharraf may have calculated that his co-operation with the coalition would give him extra leverage. But, if so, it appears that he underestimated the extent to which terrorism has been redefined in global diplomacy since 11 September.

Western governments became increasingly explicit in their demands that Pakistan stop what they called cross-border terrorism.

But they have also had to calculate the risks of destabilisation inside Pakistan.

October's parliamentary elections - the first since the 1999 coup - will inevitably be a testing time.

For the international community, it is even more reason that the crisis on the India-Pakistan border needs to be more than a war put on hold.