The top military official in the U.S. said that while he supports President Barack Obama’s plan to gradually withdraw troops from U.S., he finds it somewhat risky.

Obama announced last night that he will ultimately bring back 33,000 US troops (about one-third of the total contingent) from Afghanistan by September 2012.

Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, told members of the House Armed Services Committee that Obama’s drawdown scheme is more aggressive and incur more risk than I was originally prepared to accept.

Mullen added that: More force for more time is, without doubt, the safer course. But that does not necessarily make it the best course. Only the president, in the end, can really determine the acceptable level of risk we must take.

Mullen also told the committee that Obama considered the views of his senior military officials but ultimately determined that the troop pullback would not frustrate efforts to stamp out the Taliban-led insurgency.

However, Mullen also pointed out the risks inherent in keeping US troops in Afghanistan for too long a time.

The truth is, we would have run other kinds of risks by keeping more forces in Afghanistan longer, he said in his opening statement. We would have made it easier for the [Afghan President Hamid] Karzai administration to increase their dependency on us. We would have denied the Afghan security forces, who have grown in capability, opportunities to further exercise that capability and to lead.

Meanwhile, at a Senate committee hearing, Secretary of State Hilary Clinton said that after 10 years in Afghanistan, the US military had broken the Taliban's momentum.

We do begin this drawdown from a position of strength, she said.

Republican Senator John McCain strongly opposed the troop withdrawal.

I'm very concerned that the president's decision poses an unnecessary risk to the progress we've made thus far, to our mission, and to our men and women in uniform, he said on the Senate floor.

Our troops are not exhausted, they are excited that after 10 years they are finally approaching victory.