Washington, Jun 11 (IANS): US Defence Secretary Ashton Carter has said Washington will play a bigger role in combating Taliban in Afghanistan.

Carter's remark signalled the US was going back on its commitment to end its campaign in the Central Asian country, Xinhua reported.

The new plan, approved by President Barack Obama, will allow US military commanders to use air power against the Taliban when necessary and allow its troops to accompany conventional Afghan forces into the field to advise and assist them.

Carter told a defence conference the expanded authority will let commanders "anticipate situations in which the Afghan security forces would benefit from our support", and is "a good use of the combat power that we have there".

The move, which would pave the way for US forces to once again directly battle the Taliban under some circumstances, comes just seven months before Obama leaves office, contrasting sharply with his campaign promise of ending the US military presence in Afghanistan.

Obama agreed to keep 9,800 American troops in Afghanistan after 2014 on the condition that the bulk of the force be focused on training and advising Afghan security forces.

Under a plan he signed off last year, the US forces there will be further reduced to 5,500 by January 2017, when he leaves office.

However, there is doubt that he could opt to keep a larger US troop presence in Afghanistan since the country is growing perilously unstable.

Obama is expected to complete an Afghanistan plan to be handed over to his successor by July 8, when the North Atlantic Treaty Organisation summit starts in Warsaw.

The plan would decide on the number of American troops remaining in Afghanistan after he leaves office.

Though more than 14 years have passed since the US launched the Afghanistan War, at least one-fifth of the country is controlled or contested by the Taliban, according to the media reports.