Qatar could face further sanctions by Arab states as a deadline to accept a series of demands from its Gulf neighbours, including closing down the television network al-Jazeera, passes on Sunday night.
Rex Tillerson, the US secretary of state, was working the phones to see whether a compromise could be reached but Qatari leaders have effectively rejected the 13 demands tabled 10 days ago by Saudi Arabia, the United Arab Emirates, Egypt and Bahrain.
Qatar's foreign minister, Sheikh Mohammed bin Abdulrahman Al-Thani, said on Saturday that the demands to shut down al-Jazeera, close a Turkish military base and cut relations with Iran had been framed to be rejected.
The demands were made by the Saudi-led allies over allegations of Qatari support for terrorism, which it denies. It has called the demands an attack on its sovereignty.
The four anti-Qatar states have only hinted at how they will respond if their ultimatum is spurned. UAE diplomats have suggested either suspending Qatar from the Gulf Co-operation Council (GCC), the regional trading bloc, or seeking to impose sanctions on countries that continue to trade with Qatar.
The UAE foreign affairs minister, Anwar Gargash, has played down suggestions of a military intervention. "The alternative is not escalation but parting ways," he said, suggesting forcing Qatar out of the six-member GCC is at present the most likely outcome.
The western-backed body was formed in 1981 by Saudi Arabia, the UAE, Kuwait, Qatar, Oman and Bahrain, in the wake of Iran's Islamic revolution and the outbreak of the Iran-Iraq war.
Last month Saudi Arabia, the UAE, Egypt and Bahrain severed their diplomatic ties with Qatar, closed their airspace to its jets and announced an economic blockade that included the closing of Qatar’s border with Saudi Arabia – its sole land link to the rest of the world and a key route for food imports.
Turkey has increased its military presence in Qatar in support of the emirate and both it and Iran have delivered food supplies.
In one of the first signs an extended blockade may have a significant impact on the country, some UK banks have ceased trading in the Qatari riyal for retail customers. The crisis has so far not hit energy exports from Qatar, which is the world’s biggest exporter of liquefied natural gas.
The US, which has 10,000 troops in Qatar in its main Middle East base, has been split in its response between the White House and Department of State.
Donald Trump has moved to rebuild Saudi ties and at a fundraiser last week again said he wanted Qatar to stop funding terrorism. But the state department has tried to take a more nuanced role as mediator, working alongside Kuwait.
The four nations called for the expulsion of named terrorists from Qatar, and an end to support of the Muslim Brotherhood and Hamas. It also wants international monitoring to end the funding of terrorists, as well as compensation reaching into billions of dollars for Qatar's alleged support for dissent inside their regimes.
In addition to al-Jazeera, a Doha-funded broadcaster, Qatar would also be required to shut a large number of news websites that the anti-Qatar nations see as supporting their opponents.
In the only two compromises canvassed so far privately, it has been suggested US Treasury officials could be installed inside the Qatar treasury to monitor flows of funds to extremists groups in Europe, and the Arabic-language al-Jazeera be brought under the same editorial control as al-Jazeera English.
The Qatari foreign minister said the Arab ultimatum was aimed not at tackling terrorism but at curtailing his country’s sovereignty.
“This list of demands is made to be rejected. It’s not meant to be accepted or – to be negotiated,” he said in Rome, where he has been attempting to build western support. “The state of Qatar instead of rejecting it as a principle, we are willing to engage in [dialogue], providing the proper conditions for further dialogue.”
He added that no one had the right to issue an ultimatum to a sovereign country. Qatar has said it is willing to talk if the blockade is lifted.
The National Human Rights Committee in Qatar has hired a Swiss law firm to investigate the human rights consequences of the Saudi-led blockade. Mr Thani said 12,000 citizens and foreign residents of Qatar had been separated by the illegal blockade, and many would be entitled to seek compensation.