US Secretary of State Rex Tillerson will embark on a personal mission today to help resolve the ongoing Gulf crisis that has threatened Washington's counterterrorism operations in the Middle East, media reports said.

Tillerson will fly to Kuwait, which has been trying to mediate in the stalemate, after Saudi Arabia, the UAE, Egypt and Bahrain warned of new sanctions against Qatar as a deadline for action passed without a breakthrough.

Tillerson plans to spend the week talking to leaders of the Gulf nations, receiving them in Kuwait or shuttling among regional capitals, The Washington Post reported quoting senior US officials.

"We've become increasingly concerned that the dispute is at an impasse at this point," The Post quoted State Department spokeswoman Heather Nauert as saying. "We believe that this could potentially drag on for weeks. It could drag on for months. It could possibly even intensify."

The terrorism-financing charge that gained Donald Trump's attention may be the easiest to resolve with increased US monitoring, administration officials said.

The officials agree Qatar's position in hosting Muslim Brotherhood officials and supporting them in other countries is troublesome, The Post said. But they believe a compromise could be worked out, perhaps by Qatar stopping its support for Brotherhood organisations in Egypt and Libya. US Defence Secretary James Mattis last week called his Qatari counterpart Khalid bin Mohammad Al Attiyah to emphasise the "importance of de-escalating tensions...so all partners in the Gulf region can focus on next steps in meeting common goals", the Pentagon said.

The moves came as Saudi Arabia and allies vowed to take additional steps after Qatar refused to accept a list of 13 demands

Source: Khaleej Times