"Dr Abdullah has indicated consistently that he will abide by the constitution," said State Department spokeswoman Jen Psaki.
"We expect the candidates and their supporters to remain committed to the process, and to the conclusion of the process."
She noted that Abdullah had called on his supporters to reject violence even though he insisted today that he had won the country's disputed election.
In a speech, Abdullah repeated claims that massive ballot-rigging had denied him victory over his rival Ashraf Ghani in the race to lead Afghanistan as US-led NATO troops withdraw from their long war against Taliban insurgents.
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But Abdullah, who was far behind Ghani in preliminary results from the runoff vote, has pulled out of the audit, and negotiations on the unity government have also ground to a halt.
"In our view the audit process is still ongoing under the supervision of the United Nations," Psaki told reporters.
"I think it was confirmed that part of the process has been completed, (but) there's more that needs to be done."
"Certainly our preference would have been to resolve this quite some time ago, but obviously we have to resolve this in the situation that we are in.