They explained that the decision was taken after their countries had gathered enough proofs on Qatar's disgraceful behavior and support of terrorism in a number of countries and after long patience and attempts to keep Doha away from supporting the terrorist groups in order to protect its political and national security.
Separately, at a joint news conference alongside British Foreign Secretary Boris Johnson, Saudi Arabian Foreign Minister Adel al-Jubeir said his country was working on a list of complaints against Qatar, according to a Saudi news channel.
Yousuf Mohamed al-Jaida, chief executive of the Qatar Financial Centre, said the majority of the contracts at risk - some $1.5 billion (1.3 billion euros) - were in the area of construction. "We are starting to see unsafe spillovers already both in the broader region but also in Africa and in Asia, there are worrying signals", she said in Luxembourg.
There was no immediate indication over why they had been detained or if it directly concerned their reporting from the kingdom.
"Each campaign is unique and when you deal internationally, they take quite a while", Caret said. The pair are now heading back to Turkey.
While plausible, Turkey's one-sided support to Qatar could damage the chances of success of its mediation efforts, experts said.More news: Ronaldo on target for Portugal
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"But what we have seen until now, there is no solid ground for these demands, that's why they didn't submit their demands yet".
Turkey plays an important role and enjoys authority in the Islamic world, and using this, Ankara intends to resolve the Qatar crisis, head of the Turkish Media Association Ekrem Kiziltas told Trend. "It remains business as usual, and we intend to keep it that way", its CEO Yousef al-Jaida said.
Qatar says the sanctions have also brought personal hardship for its citizens who live in neighboring countries or have relatives there. The countries that imposed the sanctions gave Qataris two weeks to leave, which expired on Monday.
When the diplomatic rift began last week Trump wrote on Twitter that his recent trip to the Middle East was already paying off, suggesting backing for Saudi Arabia in the dispute.
Earlier this month, Turkey's parliament fast-tracked the approval of a separate agreement with Qatar that allowed troops to be deployed to a Turkish military base in the Gulf state.