Storied Army Unit Moving Into Afghanistan's East With the Afghanistan war's endgame approaching, the Army's storied 1st Infantry Division is preparing to take command in the eastern provinces, where the strategy calls for a renewed push this year even as U.S. and allied forces draw down in less violent parts of the country. After months of carefully sequenced training at Fort Riley for what will be its first Afghanistan command tour, the 1st Infantry will take over in April for the 1st Cavalry Division in a mostly mountainous sector that spans 14 provinces and includes 450 miles of the Afghanistan-Pakistan border. Insurgent attacks in that region increased last year even as they declined substantially in the south. The U.S. and its NATO allies expect to put more emphasis this year on shifting to a support role after a decade of combat, with Afghan forces taking a more prominent role, especially in the south. In the eastern provinces, a lot of tough fighting is still in the offing. "We can't take our foot off the throat of the insurgency," the 1st Infantry's commanding general, Maj. Gen. William Mayville, said in an Associated Press interview Monday at his headquarters on Custer Hill, overlooking this sprawling post on the banks of the Kansas River. This image released by the U.S. Army shows Maj. Gen. William Mayville, the 1st Infantry's commanding general. As the Afghan war's endgame approaches, the U.S. Army's storied 1st Infantry Division _ the Big Red One _ is preparing to take command in the eastern provinces of Afghanistan. The U.S. strategy is calling for a renewed push this year against a complex and resilient insurgency. The 1st Infantry will take over in April for the 1st Cavalry Division in a mostly mountainous sector that spans 14 provinces and includes 450 miles of the Pakistan border. (AP Photo/U.S. Army) Close Mayville and his team will be arriving in Afghanistan at an especially tense time, following Afghan outrage over what American officials call the accidental burning of Muslim holy books last month and the massacre of 16 Afghan civilians March 11, allegedly by a U.S. soldier, Staff Sgt. Robert Bales. Mayville, an Iraq war veteran who is one of the Army's most experienced Afghanistan hands, said the key to success is ensuring that sufficiently trained Afghan security forces - both army and police - are connected to an adequately capable Afghan government. He said he is encouraged by what he believes is a growing pool of capable and committed Afghan military leaders. "None of this works if you then can't connect all of this progress to the efforts to build a viable Afghan government at the local, provincial and national level," he said. Without commenting on the shootings or the Quran burnings, Mayville said he believes the U.S. and its allies will stick to their current strategy even as President Hamid Karzai pushes for an early end to the presence of foreign forces in Afghan villages. Mayville's view has been echoed by numerous military and administration officials, including President Barack Obama, even though a majority of Americans say it's time to leave Afghanistan after 10 years. "I don't see us coming off of this campaign plan," he said. And I don't see anything where the trajectory of our campaign necessarily has been altered or changed. The top American commander in Afghanistan, Marine Gen. John Allen, is due to open three days of congressional testimony Tuesday. He is expected to face tough questions from lawmakers on the implications of recent U.S. setbacks and on Karzai's demand for a pullout from rural areas. Since Feb. 1, seven U.S. servicemen have been killed by their Afghan allies. Mayville's task in the eastern sector is complicated by the makeup of an insurgency that is more diverse than in the Pashtun-dominated south. "The east is the most complex area of all the battle spaces" in Afghanistan, Mayville said.