Britain’s foreign secretary has said that a major diplomatic crisis in the Gulf will end only when “measured and realistic” conditions are discussed, in comments made shortly after a 13-point ultimatum was reportedly issued by a Saudi-led bloc of countries that have cut ties with Qatar.

“Gulf unity can only be restored when all countries involved are willing to discuss terms that are measured and realistic,” Boris Johnson said on Friday, according to a statement published by the UK’s Foreign and Commonwealth Office.

“The UK calls upon the Gulf states to find a way of de-escalating the situation and lifting the current embargo and restrictions which are having an impact on the everyday lives of people in the region,” Johnson added.

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The situation between the Gulf neighbours sharply deteriorated on June 5 after Saudi Arabia, the United Arab Emirates, Bahrain and Egypt severed ties with Qatar and imposed a blockade against it over allegations the country supports “terrorism”.

The Saudi-led bloc of countries has not provided any evidence, and Qatar has repeatedly denied the allegations as baseless.

READ MORE: Qatar-Gulf crisis – Your questions answered

Earlier on Friday, reports emerged that the bloc had given Qatar 10 days to comply with the demands, which included shutting down the Al Jazeera network, close a Turkish military base and scale down ties with Iran.

In the 13-point list, the countries also demand that Qatar sever all alleged ties with the Muslim Brotherhood and with other groups, including Hezbollah, al-Qaeda and the Islamic State of Iraq and the Levant (ISIL, also known as ISIS).

The document does not specify what the countries will do if Qatar refuses to comply.

Meanwhile, the United Nations said on Friday it is deeply worried about the situation in the Gulf and hoped the crisis to be solved through dialogue that should be consistent with international law, including human rights.

“We continue to follow the situation with deep concern. We are aware of reports of a list of demands on Qatar. We are not able to comment in detail on, or confirm such a list,” UN spokeswoman Eri Kaneko said.

“We hope that the countries involved resolve the situation through dialogue,” said Kaneko. “We are ready to assist if requested by the parties.”

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Earlier this week, US Secretary of State Rex Tillerson insisted that Qatar’s neighbours provide a list of demands that was “reasonable and actionable” to move the diplomatic crisis towards a solution.

On June 12, Johnson had urged the Saudi-led bloc of countries “to ease their blockade” on Qatar and find an immediate solution to the impasse through mediation.

“I call on all states to take immediate steps to de-escalate the situation and to find a rapid resolution through mediation,” Johnson said at the time, adding that he was “concerned by some of the strong actions” taken by Saudi Arabia, the UAE and Bahrain.

The Qatari government has described the blockade as a “violation of international law”.