The unfolding situation with Qatar also has ties to possible Russian interference.
I won't name other countries, but we are not done solving the problem, but we will solve that problem. "This situation is a strategic opportunity to seize, not a crisis to manage", he said. "Qatar remains critical for coalition air operations in the fight against ISIS and around the region".
Launching an extraordinary allegation against a key United States military partner, Trump derided what he called Qatar's "extremist ideology in terms of funding" terrorist groups, an accusation Qatar has repeatedly and vehemently denied.
Qatar hosts the Al-Udeid military base, the largest USA airbase in the Middle East that is central to the fight against the Islamic State group in Iraq and Syria. A picture on Facebook showed a supermarket displaying food from Turkey including milk, eggs and chicken.
Commenting on the criticism against Turkey for providing food supplies and military support to Qatar, Erdogan said: "Our friends in the Gulf were not bothered by the U.S. base in Qatar but why are they concerned about a Turkish base".
"Until today I have not witnessed Qatar give support to terror", Erdogan said in Istanbul, adding that the Arab states "declare foundations established to provide different services as terror organizations". He said he had been consulted in advance by nations that "spoke to me about confronting Qatar", a country he said historically has been a "funder of terrorism at a very high level". Some countries said they would cut sea and air traffic to Qatar, as well as expel Qatar's diplomats and citizens.More news: Apple New, Faster iMacs & MacBooks Plus macOS High Sierra
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Qatar acknowledges its links to these groups but denies that it supports terrorism.
Qatar's Sheikh Tamim Bin Hamad al-Thani and President Trump during a bilateral meeting at a hotel in the Saudi capital Riyadh.
"There is no need to hoard commodities", one of them said.
"The elements of a solution are available", Tillerson said at the State Department.
Germany's foreign minister, Sigmar Gabriel, had previously attributed the escalation of the dispute to what he called a risky "Trumpification" of regional politics.
Turkey's parliament has approved deploying troops to a base in Qatar and Iran has offered to send food.
Meanwhile, Bahrain "stressed the necessity of Qatar's commitment to correct its policies and to engage in a transparent manner in counter-terrorism efforts", its official BNA news agency said. But this will come at the cost of other USA foreign policy objectives in the region. Qatar is home to the biggest American airbase in the region, with about 10,000 troops. Projects include soccer stadiums for the 2022 World Cup. The riyal currency has tumbled and the cost of insuring Qatari debt against default has risen.
The blacklist is the latest allegation by Saudi Arabia and its allies against Qatar since the crisis erupted late last month. Those on the list, including the former interior minister, could not be reached for comment.
Also named were Doha-based Muslim Brotherhood spiritual leader Yusuf al-Qaradawi and Qatari-funded charities.