GUADALAJARA, Mexico, Aug 10 (Reuters) - The White House said on Monday that President Barack Obama has a "winning" strategy in Afghanistan and enough forces on the ground to achieve U.S. goals despite advances by the Taliban. The assurances came as the top U.S. commander in Afghanistan warned that the Taliban were gaining momentum, while gunmen and bombers stormed government buildings near Kabul just 10 days before a presidential election, White House spokesman Bill Burton said that Obama had authorized 21,000 new troops for Afghanistan since taking office in January and not all of these were on the ground yet."The president's strategy hasn't fully been implemented just yet. But we do believe that with the strategy that we have, with assets that we're putting on the ground, that we are going to be able to achieve the goals that we're trying to achieve," Burton told reporters on Obama's Air Force One flight back to Washington from a North American summit in Mexico. U.S. Army General Stanley McChrystal, who will soon present an assessment of the Afghan war, said in a newspaper interview published on Monday that the resurgent Taliban have forced a change of tactics on foreign forces and that record casualty figures would remain high for some months. [ID:nSP438927] "It's a very aggressive enemy right now," McChrystal, who is also the NATO commander in Afghanistan, told The Wall Street Journal (http://online.wsj.com/). "We've got to stop their momentum, stop their initiative. It's hard work." The White House said McChrystal was preparing a thorough assessment of the situation on the ground in Afghanistan and U.S. officials will see what his review turns up. "Obviously the president is in close contact with his commanders on the ground, but ... thinks that the strategy that he put in place is a winning one," Burton said. Violence across Afghanistan this year had already reached its worst levels since the Taliban were ousted by U.S.-led Afghan forces in 2001 and escalated dramatically after major offensives were launched in southern Helmand province in July. Three Afghan police and two civilians were killed in a strike by Taliban gunmen and suicide bombers on government buildings near Kabul on Monday. [ID:nSP497047] Washington plans to increase the number of its troops to about 68,000 by year's end, more than double the 32,000 it had stationed in Afghanistan at the end of 2008. McChrystal may ask for more after he submits his strategy review in coming weeks. For more stories on Afghanistan, click on [ID:nAFPAK]. (Reporting by Patricia Zengerle and Steve Holland; Editing by Xavier Briand)
Armed men, who recently returned to their village after a military offensive against the Taliban, walk past a school girl while providing security in Buner district about 220 km (137 miles) ...
