U.S. officials watched with growing concern today as reports suggested Pakistan was massing troops to the India border.
Such a move raises double-barreled worries: A possible confrontation between two nuclear powers and a shift by the Pakistani military away from battling the Taliban along its western Afghan edge.
U.S. intelligence and military officials were still trying to determine what Troop Formations are on the move, and, what Pakistan's intent may be.
Officials spoke on condition of anonymity to discuss intelligence matters.
Adm. Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, was in Pakistan twice this month, and as many as seven times in the past year. In recent meetings with senior Pakistani leaders he has urged restraint and encouraged both sides to find ways to work together.
One senior military official said today that the U.S. is monitoring the issue, but still could confirm assertions from Pakistani intelligence officials that some troops were on the move, heading to the Indian border.
A key concern for U.S. officials is that some of those troops may have been stationed along the volatile Afghan border, and were being diverted to the Indian side.
Defense Secretary Robert Gates and Mullen, who have both been in the region in recent weeks, have expressed the hope that Pakistan would stay focused on fighting militants in its mountainous northwestern Federally Administered Tribal Areas, or FATA.
The Pakistan Army's 14th Division is being redeployed to the towns of Kasur and Sialkot, close to the Indian border.
Analysts said the redeployment is likely meant as a warning to India not to launch missile strikes against militant targets on its territory. It is not likely an indication that the two countries are about to descend into war, analysts said.
"They should concentrate on the real issue: how to fight against terrorists and how to fight against and bring to book the perpetrators of [the] Mumbai terrorist attack," said Indian Foreign Minister Pranab Mukherjee.
Indian Prime Minister Manmohan Singh met with the chiefs of the army, navy and air force to discuss "the prevailing security situation," according to an official statement.

India is warning its citizens that it would be unsafe to go to Pakistan amid heightened tension.
Pakistan has begun moving thousands of troops away from the Afghan border toward India.
Pakistan has moved Major Formations of the XVI Corps (Nagrota Corps) to the Line of Control (which divides Pakistani and Indian portions of Kashmir).
Pakistan Army had moved its 10th Division to Lahore.
Infantry out of South Waziristan on the move.
The 3rd Armoured Brigade is heading towards Jhelum.
Warplanes flying over major cities.
Pakistan canceled leave for members of its armed forces Friday, beefing up its military strength in case of conflict with India over the deadly Mumbai attacks, a senior military official said.
The military remains on alert, but it has not moved additional troops to the Indian border, said the official, speaking on condition of anonymity because he was not authorized to talk to the media.
In response, India said it had not canceled any time off for its military. "People are taking leave, no problem," said Indian Defense Ministry spokesman Sitanshu Kar. "We have an optimum number, which is always maintained."
Pakistan accused Indian fighter jets of violating its airspace on two separate occasions more than a week ago, raising the possibility of conflict. But Pakistani officials subsequently played down the incidents, saying the violations, which India denied altogether, were likely accidental.
Pakistani fighter jets have flown over several of the country's major cities in recent days after the alleged airspace violations.
Pakistan and India have fought three wars since their independence from Britain in 1947, but the stakes are even higher now that both countries have nuclear weapons.
Hoax call put Pakistan on high alert South Asian regional tensions mounted last week after nuclear-armed Pakistan entered a state of “high alert” after receiving a phone call, now believed to be a hoax, from India’s foreign minister Pranab Mukherjee to Pakistan’s president Asif Ali Zardari the day that terrorist attacks on Mumbai concluded.
The caller allegedly threatened to attack Pakistan if measures were not taken to track down militants associated with the Mumbai terrorist strikes.
On Saturday, Pakistan’s Dawn newspaper reported on the incident: ”Whether it was mere mischief or a sinister move by someone in the Indian external affairs ministry, or the call came from within Pakistan, remains unclear, and is still a matter of investigation. But several political, diplomatic and security sources have confirmed to Dawn that for nearly 24 hours over the weekend the incident continued to send jitters across the world. To some world leaders the probability of an accidental war appeared very high.”
Senior Pakistani government officials confirmed the report and said the matter was under investigation, which involves efforts to trace the origin of the phone call and how it was directed to Mr Zardari.
One senior Pakistani official said Indian officials have denied that the call ever originated from Mr Mukherjee, raising the possibility that the call was a hoax. However, the Pakistani official insisted that the calling number was traced back to Mr Mukherjee’s office in New Delhi.
”We are looking at two possibilities right now. Either it was somebody from the Indian foreign ministry who used the foreign minister’s number to pull a prank or some very sophisticated technology was used to fabricate the calling number” said the official who spoke to the Financial Times on condition of anonymity.
Reporting on the reaction to the phone call, DAWN wrote; ”Intense diplomatic efforts that started late on Friday went on throughout the following day. During this period phone calls were made from Islamabad to some of the top officials and diplomats in Washington, including Condoleezza Rice, and the US Secretary of State called Mr Mukherjee and others in India in a night-long effort to understand what might have gone wrong, and to persuade the two sides to bring down the temperature.”
A senior western diplomat commenting on the report said, the incident prompted Mr Zardari to call Condoleezza Rice, US Secretary of State, to convey Pakistan’s anxiety over worsening security conditions.
Ms Rice then called Mr Mukherjee to inquire about the incident during which Mr Mukherjee categorically denied making the phone call in the first place. The western diplomat also revealed that before Ms Rice’s phone call to Mr Mukherjee, the unknown caller allegedly using the Indian foreign minister’s phone from his office, also called the US secretary of state, but was not put through to speak to her.
”Could this incident have caused a war between India and Pakistan? That is the big fear of an accidental situation coming together” said the western diplomat. ”It seems that standard procedures should have been followed in Pakistan such as someone taking down the Indian telephone number and then returning the call. That obviously did not happen, in what seemed at the time like a building up crisis situation”.