By ROBERT BURNS
AP National Security Writer
WASHINGTON (AP) - President Barack Obama declared Monday he is sticking to his war strategy of using U.S. troops to advise and mentor Afghan forces, even as a suddenly growing number of Americans are being gunned down by the very Afghans they are training to take on insurgents.
In just the past 10 days, Afghan forces have attacked their coalition partners seven times, killing nine Americans. For the year there have been 32 such incidents, killing 40, compared to 21 attacks killing 35 troops in all of 2011.
"We are deeply concerned about this, from top to bottom," Obama told a White House news conference. But he said the best approach, with the fewest number of deaths in the long run, would be to stick to the plan for shifting security responsibilities to the Afghans.
"We are transitioning to Afghan security, and for us to train them effectively we are in much closer contact _ our troops are in much closer contact with Afghan troops on an ongoing basis," Obama said. "Part of what we've got to do is to make sure that this model works but it doesn't make our guys more vulnerable."
That vulnerability, however, has been exposed in a strikingly deadly way in recent days.
U.S. officials offer two main theories for why Afghan security forces are turning their weapons on Western partners: infiltration by the Taliban and a U.S.-Afghan culture clash.
Both of those root causes suggest that the problem may get worse as American and other coalition forces shift further into an adviser/mentor role. And that, in turn, raises questions about U.S. ability to train and shape the Afghans into a force that can stand up to the Taliban insurgency after foreign forces end their combat role in 2014.
Jacqueline L. Hazelton, a visiting assistant professor at the University of Rochester, who has extensively studied counterinsurgency strategy, sees the attacks stemming from a combination of Afghan resistance and resentment.
"As disturbing as the attacks are as a Taliban tactic, the broader popular anger revealed - among those the mission is supposed to be most closely allied with and most directly useful to - is even more dangerous for the longer term and reveals a greater rot within," Hazelton said in an email exchange.
Pentagon press secretary George Little said U.S. officials believe the current approach is solid, despite the surge in attacks.
"In the face of this problem, we remain strongly committed to the strategy we have put in place," he said. "The strategy is working, and suggestions that it is fundamentally imperiled at this point are just wrong."
As recently as last week, Defense Secretary Leon Panetta called such attacks "sporadic" and a sign of Taliban desperation. But as the assaults continued through the week, he consulted with his top commander in Kabul and then on Saturday called Afghan President Hamid Karzai to express concern. Obama said Monday he would do the same.
"We've got to make sure we're on top of this," Obama said.
Obama's Republican election rival, Mitt Romney, said Monday in New Hampshire that the U.S. goal ought to be to "transition from our military to their military as soon as possible," in a way that prevents Afghanistan from collapsing and reverting to being a launching pad for terrorist attacks on the U.S.
Obama said he discussed the problem Monday with the chairman of the Joint Chiefs of Staff, Army Gen. Martin Dempsey, who was already in Kabul to talk to American and Afghan officials about how to halt the killings.
Dempsey said upon his arrival in Kabul that it was important for Karzai and other top government officials to publicly denounce the insider killings, according a Pentagon account of his remarks.
Dempsey's office at the Pentagon issued a statement Monday saying he is convinced, after discussing the insider threat with his Afghan counterpart, Gen. Sher Mohammed Karimi, that the Afghans "understand how important this moment is."
"In the past, it's been us pushing on them to make sure they do more," Dempsey was quoted as saying. "This time, without prompting, when I met General Karimi, he started with a conversation about insider attacks - and, importantly, insider attacks not just against us, but insider attacks against the Afghans, too."
Dempsey has acknowledged that efforts begun a year ago to improve the vetting of Afghan recruits have yet to solve the problem.
Olga Oliker, an analyst at the Rand Corp. who studies Afghan security forces, said the checks are inevitably spotty, which makes training even more difficult.