Reuters PAKISTAN and the United States depend on one another too much to allow the deaths of two dozen Pakistani soldiers in air strikes by NATO forces on Saturday to cause a definitive rupture. But the incident, the latest in a series of embarrassments this year to bedevil the relationship between two ostensible allies, will only aggravate the mistrust between the countries, and will require quick diplomatic work to contain. Analysts and Western officials who track the relationship said a speedy, thorough investigation to find out what happened, establish responsibility and make amends is vital, although any reconciliation may be harder to achieve if NATO forces conclude the Pakistani side started the fight. “They still have a great deal of co-dependence,” said Shuja Nawaz, an authority on the Pakistani military at the Atlantic Council think tank in Washington. “The United States needs Pakistan until it wraps up kinetic operations in Afghanistan.” The US plans to have most troops out of Afghanistan by the end of 2014. “Pakistan, of course, is still fairly heavily dependent on US financial and military support,” Nawaz said. “But the way things have been going this past year, it's one event after another.” All the details of what happened in the latest incident, in Pakistan's Mohmand tribal agency, are not yet publicly known. NATO helicopters and fighter jets based in Afghanistan attacked two Pakistan military outposts on Saturday, killing 24 Pakistani soldiers in what Islamabad called an unprovoked assault. A Western official and a senior Afghan security official on Sunday said that NATO and Afghan forces came under fire from across the border with Pakistan before NATO aircraft attacked the Pakistani forces. An early test of how much the US-Pakistani relationship has been hurt may come from how well the sides cooperate with one another and with the Afghan authorities to establish precisely what happened on the border. The key questions include who fired first and from where; why NATO and Pakistani forces appear to have been unable to communicate so as to prevent the Pakistani deaths; and whether NATO helicopters knew they had entered Pakistani territory. “All of this is extremely murky and needs to be investigated,” said an Obama administration official who spoke on condition of anonymity. “Our goal today is ... that the investigation gets mounted in a way that is confidence-building on all sides,” the official added. While there have been suggestions Pakistan could seek to improve its ties to China as a strategic counterweight to the United States, analysts dismissed this idea. Islamabad receives significant amounts of military hardware from Beijing and their armed forces are close but former US ambassador to Pakistan Teresita Schaffer, said the United States is a source of two things Beijing does not provide: top-flight weaponry and extensive cash assistance. Even if there is no radical rupture, relations are unlikely to improve quickly. “The US-Pakistan relationship appears destined to lurch from crisis to crisis unless and until the two sides can reach some kind of understanding on the way forward in Afghanistan,” said Lisa Curtis of the Heritage Foundation think tank. With NATO planning to intensify its operations in eastern Afghanistan next year to try to cut off insurgent routes from Pakistan, Curtis said “the situation is likely to get worse before it gets better.” __