Qatar's foreign minister is set to meet his US counterpart in Washington, DC, after the US state department voiced confusion over the Saudi-backed embargo of the country.
Sheikh Mohammed bin Abdulrahman Al Thani's meeting with Rex Tillerson, US secretary of state, on Tuesday will come just days after Qatar dismissed a list of demands from Bahrain, Egypt, Saudi Arabia and the UAE.
The ultimatum demands that Qatar comply with 13 points in return for an end to a three-week-old diplomatic and trade blockade of the country.
In an interview with France 24 Arabic, Sheikh Mohammed bin Abdulrahman has said Qatar has always "abided by international laws" and played a key role in the international coalition battling the Islamic State of Iraq and the Levant (ISIL) group.
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The four Arab governments announced earlier this month they were suspending all ties with Qatar, accusing it of support for "extremist groups", a claim Qatar denies.
Tillerson has urged a diplomatic solution, and the US has been pushing for a clear list of grievances that are "reasonable and actionable".
Underscoring the administration's mounting frustration over the Saudi bloc's role in the crisis, Heather Nauert, state department spokesperson, recently called on the parties to settle their differences.
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Nauert called into question whether Qatar's alleged support for terrorism was the true cause of the crisis, or whether there was an underlying political dispute.
In addition to cutting diplomatic ties, Qatar's neighbours expelled Qatari citizens, closed their airspace to Qatari carriers and blocked its only land border, vital for food imports.
Qatar is home to the largest US base in the region, Al-Udeid, while Bahrain is home to the US navy's Fifth Fleet.