"I don't doubt that there will be members of the Taliban or violent extremists that seek to disrupt the will of the Afghan people," White House spokesman Robert Gibbs told reporters at his daily news briefing.

"That's not going to be successful. The Afghan people are going to decide who will run their next government, and we're confident of that," Gibbs said.

Gibbs said the troops that were authorised to go by the President to create a security environment that allowed us to have an election -- we saw the same type of cowardly violence leading up to the first election.

He said the Obama Administration is conducting a comprehensive assessment. President Barack Obama has so far held six situation room meetings at the White House running into more than 17 hours.

Obama is scheduled to meet Admiral Mike Mullen, Chairman of the Joint Chiefs of Staff, to discuss with him ongoing assessment in Afghanistan and Pakistan.