TOKYO- President Barack Obama said on Friday he would make a decision soon on his Afghanistan strategy and the plan would make clear the goal is for Afghans to provide for their own security.

He added that the U.S. commitment in Afghanistan could not be open-ended.

Asked at a news conference in Japan what information he still needed to enable him to make a decision, Obama said it was not matter of awaiting a piece of data.

Instead, he said, It's a matter of making certain that when I send young men and women into war and devote billions of dollars in U.S. taxpayer money, that it's making us safer and that the strategies that are in place, not just on the military side but also on the civilian side, are coordinated and effective in our primary goal.

The ultimate aim, he said, was to protect America and its allies from attack.

The president is weighing several options for boosting U.S. force levels in Afghanistan, a decision likely to escalate America's involvement to confront a resurgent Taliban and their al Qaeda allies.

Proposed options range from dispatching 10,000 to about 40,000 additional troops, according to a U.S. official.

Republicans have criticized Obama for taking so long to announce his decision and a new poll by Zogby Interaction found that nearly half of those surveyed viewed the lengthy deliberations as a sign of weakness by the president.

I recognize that there have been critics of the process, Obama said. They tend not to be folks who I think are directly involved in what's happening in Afghanistan.

Obama said his deliberations were not an academic exercise but a necessary process in order to make sure that we're making the best possible decisions.

He said that when he does arrive at a decision, he wants to be able to clearly explain to the American people the aim of his plan and what it will entail.

It will also, I think, send a clear message that our goal here ultimately has to be for the Afghan people to be able to be in a position to provide their own security and that the United States cannot be engaged in an open-ended commitment, Obama said.

He made his comments on Afghanistan at the beginning of a nine-day trip to Asia.

As Obama left Washington Thursday, news reports said that his ambassador to Kabul, ex-military commander Karl Eikenberry, had expressed concern about sending more troops until Afghan President Hamid Karzai's government improved its performance in fighting corruption.