ISLAMABAD, Pakistan - Pakistan's army said Tuesday that its forces have orders to open fire if U.S. troops launch another raid across the Afghan border, raising the stakes in a dispute over how to tackle militant havens in Pakistan's unruly border zone. Adm. Mike Mullen, the U.S. chairman of the joint chiefs of staff, arrived in Pakistan late Tuesday amid the increased tensions. Mullen planned to meet with top civilian and military leaders to discuss a range of issues, including ways to improve coordination and cooperation along the Pakistan-Afghan border. Pakistan's government has faced rising popular anger over a Sept. 3 ground attack by U.S. commandos into South Waziristan, a base for Taliban militants killing ever more U.S. troops in Afghanistan. Pakistan says about 15 people were killed, all of them civilians. The new firing orders were disclosed by Pakistani army spokesman Maj. Gen. Athar Abbas in an interview Tuesday with The Associated Press. Abbas said Pakistani field commanders have previously been tolerant about international forces crossing a short way into Pakistan because of the ill-defined and contested nature of the mountainous frontier. "But after the (Sept. 3) incident, the orders are clear," Abbas said. "In case it happens again in this form, that there is a very significant detection, which is very definite, no ambiguity, across the border, on ground or in the air: open fire." The statement was the strongest since Gen. Ashfaq Parvez Kayani, Pakistan's army chief, raised eyebrows last week by vowing to defend Pakistani territory "at all cost." Abbas would not say whether the orders were discussed in advance with U.S. officials. Rep. Gary Ackerman, Democratic chair of the House of Representatives Foreign Affairs Subcommittee on South Asia, and other lawmakers expressed concern about Abbas' comments at a hearing Tuesday to examine a Bush administration request to fund an upgrade of Pakistan's aging fleet of F-16 fighter planes. Responding to the concerns, Donald Camp, deputy assistant secretary of state for South Asian affairs, said: "I cannot envision a situation where we would find ourselves in a shooting situation with Pakistan." "We are partners with Pakistan. We have been close friends for years," he said. President Asif Ali Zardari, the newly elected successor to U.S. ally Pervez Musharraf, declined to comment on the order to use lethal force on American troops, telling reporters in London: "I don't think there will be any more" cross-border operations by the U.S. U.S. military commanders complain Islamabad has been doing too little to prevent the Taliban and other militant groups from recruiting, training and resupplying in Pakistan's lawless tribal belt. Pakistan acknowledges the presence of al-Qaida fugitives and its difficulties in preventing militants from seeping into Afghanistan. However, it insists it is doing what it can and paying a heavy price, pointing to its deployment of more then 100,000 troops in the increasingly restive northwest and a wave of suicide bombings across the country. Mullen, who is on his fifth visit to Pakistan since assuming his post, intended to "discuss ongoing operations in the border region" with Prime Minister Yousuf Raza Gilani and army chief Kayani, said Mullen spokesman Lt. Col. Gary Tallman. "He has been focused keenly on working more closely with the Pakistani military to improve coordination and effectiveness in operations against extremist safe havens in the border regions," Tallman said. American officials have confirmed U.S. forces carried out the Sept. 3 raid near the town of Angoor Ada in South Waziristan but have given few details of what happened. Abbas said that Pakistan's military had asked for an explanation but received only a half-page of "very vague" information that failed to identify the intended target. He said the dead all appeared to be civilians, adding: "These were truck drivers, local traders and their families." Abbas said Pakistani officials had to consider public opinion, which is skeptical of American goals in the region and harbors sympathy for militants fighting in the name of Islam. "Please look at the public reaction to this kind of adventure or incursion," Abbas said. "The army is also an extension of the public, and you can only satisfy the public when you match your words with your actions." However, some analysts forecast that the consequences of alienating the United States would stay the army's hand. "If an American soldier were to die because of Pakistani military firing that would damage the Pakistani-American relationship for years to come," said Craig Cohen, an analyst at the Center for Strategic and International Studies in Washington. The threat "might stir nationalist sentiment in Pakistan and play well politically, but it's just not realistic," he said. Pakistan's military has won American praise for a six-week offensive against militants in the Bajur tribal region that Pakistani officials say has killed 700 suspected insurgents and about 40 troops. Troops backed by warplanes killed 15 more alleged militants Tuesday, officials said. In the same timeframe, there has been a surge in missile strikes apparently carried out by unmanned U.S. drones. Such attacks killed at least two senior al-Qaida commanders earlier this year. All of those strikes have been well to the south of Bajur, in areas where Pakistani authorities have sought peace deals in order to gain respite from militant attacks. Abbas said that while they were tackling the "mega-sanctuary" in Bajur, they didn't have the forces to fight militants across the tribal belt all at one time. At least two other areas have been earmarked for military operations, he said. Jalaluddin Haqqani, a formidable Taliban commander whose relatives were reportedly among the dead in one of the recent missile attacks, was definitely in Afghanistan, he added. Abbas denied the new order had been put into practice before dawn on Monday, when U.S. helicopters reportedly landed near Angoor Ada only to fly away after troops fired warning shots. Abbas insisted no foreign troops had crossed the border and that "trigger-happy tribesmen" fired the shots. Pakistani troops based nearby fired flares to see what was going on, he said. The U.S. military in Afghanistan said none of its troops were involved. ___
