Pakistan on Saturday ordered an Indian diplomat who was allegedly caught with "sensitive documents" to leave the country, prompting a reciprocal expulsion by India, in a setback to the historic rivals' shaky peace process.

Pakistani officials accused Deepak Kaul, a visa official at the Indian High Commission in Islamabad, of "undesirable activities." He was told to leave the country early next week.

Kaul was caught by Pakistani agents "red-handed with sensitive documents," a Pakistani government official said on condition of anonymity because he was not authorized to speak to the media. He declined to give further details.

India responded a few hours later, ordering Mohammed Rafique, a visa official at Pakistan's High Commission in New Delhi, to leave India by Aug. 7, Pakistan's Foreign Ministry said.

Ministry spokeswoman Tasnim Aslam called the expulsion "unfortunate and clearly retaliatory."

The tit-for-tat expulsions do not represent a major breach in relations between Pakistan and India, but reflect the growing strain on a peace process started in early 2004 to resolve six decades of hostility.

"Such action as has been taken by the government of Pakistan cannot but undermine the bilateral relations between the two countries," the Indian foreign ministry said in a statement.

The statement said Pakistani agents detained Kaul on the Islamabad-Lahore Highway as he was traveling to the international border checkpoint at Wagah to fetch his family.

He was handcuffed, blindfolded and taken to an undisclosed location where he was kept for about five hours, before he was handed over to Indian diplomats, the statement said.

Aslam said Kaul was "caught red-handed" and that he has been handed over to the Indian High Commission. He has been told to leave by early next week.

"We have evidence of his undesirable activities," she said.

T.C.A. Raghawan, deputy high commissioner at the Indian mission, confirmed that Kaul has been ordered to leave, but denied he was involved in any unlawful activity.

"We reject these allegations," he told the AP.

Pakistan and India have a history of bitter relations, and have fought three wars since the partition of the subcontinent in 1947 after independence from Britain. Tensions have eased palpably in the last two-and-a-half years, but ramped up again after the July 11 bombings on the Bombay rail network killed 207 people.

India consequently postponed a round of peace talks with Pakistan, saying the attackers in Bombay had received support from across the border in Pakistan, which Pakistan denied.

Pakistan and India have often expelled each other's diplomats in the past, usually over spying allegations. But Saturday's expulsions were the first since the two countries agreed in January 2004 to resume peace talks, the Indian statement said. The last such expulsions were ordered in 2003.