NEW DELHI, May 3: Indian Prime Minister Atal Bihari Vajpayee responded promptly but cautiously to Prime Minister Zafarullah Khan Jamali's invitation on Saturday to visit Islamabad, saying careful preparation was needed for a summit meeting and problems of cross-border terrorism had to be resolved.

Writing back to Mr Jamali within hours of receiving the invitation, Mr Vajpayee said: "Careful preparation needs to be made on the ground so that a meaningful engagement can be made at the highest level".

"We have repeatedly stressed on the need to create a conducive atmosphere for a sustained dialogue, which necessarily requires an end to cross-border terrorism and destruction of its infrastructure," he added.

Pakistan's Foreign Minister Khurshid Mehmood Kasuri told an Indian TV channel that Pakistan was prepared to give international guarantees for the two proposed gas pipelines from Iran and Turkmenistan which would pass through its territory to feed India's needs.

Keeping a similar business aspect in focus, Mr Vajpayee too recalled his discussion with Mr Jamali on the telephone and urged him to help revive suspended air links between the two countries.

Pakistani diplomats in New Delhi said their acting high commissioner Munawwar Sayeed Bhatty was summoned by the foreign ministry on Friday and handed a copy of Mr Vajpayee's address to parliament.

Mr Bhatty was also told that the prime minister's reference to the revival of air links included both landing rights and permission to fly in each other's air space.

The diplomats said Mr Jamali's formal letter had come in response to remarks earlier by the Indian foreign ministry that it had not received anything officially from Pakistan about Mr Vajpayee visiting Pakistan.

Mr Jamali's invitation came a day after the two countries agreed to restore diplomatic ties.

India had announced on Friday that it will send its high commissioner to Islamabad and restore air links with Pakistan -- a gesture that Pakistan has reciprocated.

But Mr Vajpayee's Bharatiya Janata Party still insists that "cross-border terrorism" must end before a dialogue can begin.

While officially any reference to American pressure is being dismissed, it was no coincidence that US Secretary of State Colin Powell called both Prime Minister Jamali and Indian Foreign Minister Yashwant Sinha on Saturday.

Welcoming Mr Vajpayee's fresh initiatives with Pakistan, Mr Powell said: "I hope that these first steps are just that -- first steps on the way to finding a way for difficulties that existed between these two nations to be resolved through goodwill and through solid conversation and dialogue."

The latest round of peace measures between India and Pakistan come just a week before the scheduled visit to the region by Deputy US Secretary of State Richard Armitage.

Welcoming the latest thaw in Indo-Pak relations, Jammu and Kashmir Finance Minister Muzaffar Baig hoped that the Vajpayee government would not treat the Kashmir problem as one of militancy.