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India made a conciliatory gesture to Pakistan on Wednesday, calling for joint monitoring of their disputed Kashmir frontier — a proposal that Pakistan played down as old and unlikely to work.

Even as the United States and Britain sent top officials to pressure the nuclear-armed rivals, they stepped up warnings asking their own citizens to leave.

In phone calls to Pakistani President Gen. Pervez Musharraf and Indian Prime Minister Atal Bihari Vajpayee, President Bush appealed to leaders of both nations to "choose the path of diplomacy."

"We want to move away from a path of confrontation to a path of cooperation," Vajpayee said earlier Wednesday, before leaving Kazakhstan, where he attended an Asian security conference along with Musharraf

Vajpayee said India and Pakistan should work together to patrol the border and verify that Islamic militants were no longer crossing into Indian-controlled Kashmir to launch attacks against Indian security forces and Kashmiris.

It was the first indication in the six-month standoff that India might cooperate with Pakistan to end the Kashmir insurgency and solve the dispute that dates to independence from Britain in 1947. Kashmir has been the flashpoint in two of the three wars between the South Asian rivals.

Pakistan's Foreign Ministry responded that if the Indian proposal were serious, it should be conveyed formally.

Such proposals could be discussed "as soon as India signifies a willingness to resume a comprehensive dialogue with Pakistan," the ministry said in a statement.

"The proposal is not new," the ministry said. "Given the state of Pakistan-India relations, mechanisms for joint patrolling are unlikely to work."

The ministry noted that a small U.N. monitoring force already had a mandate to patrol the confrontation line in Kashmir and that it "may be expanded to perform this role more effectively."

India has previously ruled this out, however, and Vajpayee said it was not necessary to have a third country check for infiltration — which Musharraf suggested Tuesday.

The international community has been scrambling to avert a potential fourth war between India and Pakistan as fears of a nuclear confrontation have escalated. Some 1 million Indian and Pakistani soldiers have been posted along the 1,800-mile frontier since December.

Musharraf suggested on Wednesday that hostilities could ease with upcoming visits by Defense Secretary Donald H. Rumsfeld and Deputy Secretary of State Richard Armitage.

In London, Rumsfeld said Vajpayee and Musharraf each recognize that war is the worst option and so they "may very well be looking for ways to tamp things down rather than see things escalate."

Rumsfeld added that "there's no question" the Kashmir crisis has distracted Pakistan from helping the United States finish the war against Al Qaeda in neighboring Afghanistan.

The exchange of artillery and gunfire by Indian and Pakistani soldiers lessened in the Himalayan region of Kashmir, where recent shelling has killed dozens of civilians on both sides. Officials said three people were killed in Pakistan by shelling. On the Indian side, the army said it killed six suspected Islamic militants in a raid on their hide-out.

In Lahore, Pakistan's second-largest city located near the Indian border, authorities on Wednesday held a civil defense drill similar to ones held in border towns for the past three days.

In Jammu, the winter capital of India's portion of Kashmir, the 1 million residents were put through a one-hour drill that plunged the city into darkness late Tuesday.

Citing the risk of intensified fighting, the State Department on Wednesday strongly urged U.S. citizens in the two countries to depart.

There are some 60,000 U.S. citizens in India and several thousand in Pakistan. The new warnings are stronger than past admonitions to Americans to consider leaving.

Britain issued a similar warning for an estimated 20,000 British nationals in India and 700 in Pakistan.

J.N. Dixit, India's former foreign secretary and ambassador to Pakistan, said that while war talk has eased in the last week, the wild card was another devastating militant attack.

"If there is another major terrorist attack anywhere in India, the fat will be in the fire," Dixit said. "India will take some visible action on the ground."

Despite the Pakistani military leader's calls for dialogue, Vajpayee declined to talk to his counterpart during the summit in Kazakhstan. India has insisted that dialogue will resume only after cross-border terrorism has ended.

Vajpayee said 3,000 Islamic militants were being trained in Pakistan-based militant camps, preparing to join the 12-year insurgency for Kashmir's independence or merger with Pakistan. At least 60,000 people, most of them civilians, have died in the insurgency.

Pakistani insists the militants had not come from its part of Kashmir.

Secretary of State Colin Powell said he had detected "a little bit of improvement" in the crisis, with somewhat less penetration by Muslim militants into the Indian-controlled part of Kashmir.

Indian Defense Minister George Fernandes, however, told Press Trust of Indian news agency that there was no evidence of any noticeable drop in infiltration.