WASHINGTON (AP) — The White House is urging candidates in Afghanistan's disputed presidential election to allow the process for addressing allegations of fraud to go forward.

White House spokesman Josh Earnest says serious allegations of fraud have been raised but have yet to be adequately investigated.

Earnest says preliminary results from a June 14 runoff vote that put candidate Abdullah Abdullah far behind rival Ashraf Ghani Ahmadzai aren't final or authoritative and may not predict the final outcome.

He says President Barack Obama spoke to Abdullah on Monday night to urge him to remain engaged and urged calm.

Abdullah earlier Monday blamed fraud for the preliminary results and said he intended to declare victory.

Earnest says such a move would jeopardize U.S. financial and security assistance to Afghanistan.