A U.S. official said Washington is urging Qatar to take steps to defuse the crisis, including signing on to proposals being drawn up the Treasury Department to strengthen controls against financing of militant groups.
But this official and a second U.S. official said it was inaccurate to single Qatar out, and that the Saudis, Emiratis and other Gulf states face similar challenges in countering terrorist financing.
Qatar's foreign minister, who is expected to travel to Washington next week, said Doha would not negotiate with its neighbors to resolve the Gulf dispute unless they first lift the trade and travel boycott they imposed two weeks ago.
"Now that it has been more than two weeks since the embargo started, we are mystified that the Gulf states have not released to the public nor to the Qataris the details about the claims that they are making toward Qatar," Nauert added.
There was no immediate comment from Riyadh or Abu Dhabi. Qatar's ambassador to the United States, Meshal Hamad al-Thani, welcomed the State Department's statement, tweeting: "We are confident in the ability of the U.S. to resolve this crisis".
Qatar has denied accusations by its neighbors that it funds terrorism, foments regional instability or has cosied up to their enemy Iran.
The first U.S. official said the dispute is driven more by economic rivalries, historical tensions and the personal dynamics of Gulf leaders than by the specific demands the Saudis and Emiratis are making on Qatar.