WASHINGTON: Secretary of State Hillary Clinton said Monday that the United States was impartial in Afghanistan's upcoming election and was ready to work with whomever voters pick.

Afghanistan on Thursday heads to the polls in its second-ever presidential election, which comes as the new US administration pours more troops in the country in hopes of bringing stability and rooting out Islamic extremists.

"The United States of America remains impartial in this election," Clinton said in a statement.

"Like the Afghan people we want to see credible, secure and inclusive elections that all will judge legitimate," she said, adding: "We look forward to working with whomever the Afghan people select as their leaders for the next five years."

While predicting challenges ahead, she said: "The Afghan people should be commended for their courage in conducting this election despite the stresses of wartime, and we and the international community are proud to support them."

President Hamid Karzai, who has ruled Afghanistan since the US-led invasion overthrew the Taliban regime in 2001, is the frontrunner but a strong campaign by former foreign minister Abdullah Abdullah could force a run-off.

US President Barack Obama is widely seen as cooler to Karzai than his predecessor George W. Bush, who enjoyed a warm relationship with the Afghan leader and frequently spoke to him by videoconference. LINK