NEW DELHI/ISLAMABAD (Reuters) - Pakistan canceled army leave and redeployed some troops Friday in a sign of rising tension with India.

Border Security Force (BSF) soldiers patrol the border at the India-Pakistan International Border Post, about 180 km (112 miles) from the western Indian city of Bikaner December 25, 2008. REUTERS/Vinay Joshi

The United States urged both sides to refrain from further raising tensions, already high after India blamed Islamist militants based in Pakistan for attacks on Mumbai last month that killed 179 people.

The latest strains followed media reports in Pakistan and India that “several” Indian nationals had been held in the last two days after bombings in the Pakistani cities of Lahore and Multan.

The foreign ministry in New Delhi warned Indian citizens on Friday that “it would be unsafe for them to travel (to) or be in Pakistan.”

Prime Minister Manmohan Singh had earlier discussed tension with Pakistan during a scheduled meeting about military pay with the chiefs of the army, navy and air force, his office said.

“The prime minister met the tri-services chiefs to discuss the pay commission issues but obviously the situation in the region was also discussed,” said an official from Singh’s office, who requested anonymity.

The South Asian neighbors both tested nuclear weapons in 1998. They have fought three wars since independence from Britain in 1947, and came to the brink of a fourth after gunmen attacked the Indian parliament in December 2001.

Although many analysts say war is very unlikely, international unease is growing.

“We hope that both sides will avoid taking steps that will unnecessarily raise tensions during these already tense times,” U.S. National Security Council spokesman Gordon Johndroe said.

“We continue to be in close contact with both countries to urge closer cooperation in investigating the Mumbai attacks and in fighting terrorism generally.”

Brooke Anderson, chief national security spokesperson for President-elect Barack Obama, who will be inaugurated on January 20, declined to comment on the current tensions.

“There is one president at a time, and we intend to respect that,” Anderson said.

While there had been no significant troop movements in either India or Pakistan, military officials in Islamabad said army personnel had been ordered to report to barracks and some troops had been moved off the Afghan border.

“A limited number of troops from snow-bound areas and areas where operations are not being conducted have been pulled out,” said a senior security official who declined to be identified.

WORRYING DISTRACTION

That is likely to worry Washington, which does not want Pakistan distracted from the battle against al Qaeda and Taliban militants on its western border.

The official declined to say where the troops had been moved to, citing the sensitivity of the issue. Pakistani media have reported some troops had been redeployed to the Indian border.

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India, the United States and Britain have blamed the Mumbai attack on Pakistan-based Islamist group Lashkar-e-Taiba, set up to fight Indian rule in the disputed Kashmir region.

Pakistan has condemned the attacks and has denied any state role, blaming “non-state actors.” It has offered to cooperate with India but denies Indian claims that it has been handed firm evidence of links to militants in Pakistan.

Islamabad has said that it will defend itself if attacked.

A senior police official in Pakistan’s Punjab province denied that any Indians had been arrested over the Lahore and Multan blasts but an intelligence agency official, who declined to be identified, said an Indian had been detained Wednesday.

Several more Indians had been detained based on information obtained from that suspect, the intelligence official said.

Increasingly frenzied media reporting on both sides of the border has fueled war speculation, affecting India’s government bond market Friday, although leaders from both countries have said war would serve no one’s interests.

Washington has joined Britain in urging restraint from India, but at the same time has demanded Pakistan act decisively to wipe out banned groups such as Lashkar-e-Taiba.

Chinese Foreign Minister Yang Jiechi also called his counterparts in New Delhi and Islamabad in the past two days.

China has long been a close ally of Pakistan, while India and Washington have been building close ties. A Chinese foreign ministry statement said Yang urged both sides to continue dialogue. China was willing to work with the international community to protect peace and security in South Asia.

A senior government official in New Delhi said Yang had suggested a meeting between Indian and Pakistani officials.

Indian Foreign Minister Pranab Mukherjee told Yang Pakistan must crack down on militants before a meeting would be possible, the official said. A crackdown on Pakistan-based militants after the 2001 parliament attack was seen by India as a sham.