Nations behind a blockade on Qatar have welcomed strong comments from President Donald Trump backing their move, but were silent on calls from his secretary of state to ease the measures.
Saudi Arabia, the United Arab Emirates (UAE), Egypt and Bahrain have cut ties, accusing Qatar of funding terrorism. Qatar denies the accusations.
The UAE hailed Mr Trump’s “leadership”.
But the states did not respond to Secretary of State Rex Tillerson’s warning of humanitarian consequences.
Mr Trump on Friday told Qatar: “Stop teaching people to kill other people.”
He said: “I decided with Rex Tillerson that the time had come to call on Qatar to end funding and extremist ideology in terms of funding.”
Mr Trump said he wanted Qatar “back among the unity of nations”.
However, the tone of his comments contrasted with those of Mr Tillerson, who had earlier said the blockade was having humanitarian consequences.
Mr Tillerson also said the ongoing row was affecting regional co-operation on countering extremism.
He said the blockade was “impairing US and other international business activities in the region” and that the US backed mediation efforts being pursued by Kuwait.
On Saturday, Saudi Arabia, Bahrain and the UAE made no mention of Mr Tillerson’s call.
In Saudi Arabia, an official source told the Saudi Press Agency that Qatar must change its policy, saying: “Fighting terrorism and extremism is no longer a choice, rather… a commitment requiring decisive and swift action to cut off all funding sources for terrorism.”
Bahrain’s official BNA news agency stressed “the necessity of Qatar’s commitment to correct its policies and to engage in a transparent manner in counter-terrorism efforts”.
UAE ambassador to the US Yousef al-Otaiba praised Mr Trump’s leadership in the face of Qatar’s “troubling support for extremism”.
He said: “The next step is for Qatar to acknowledge these concerns and commit to re-examine its regional policies.”
Monday’s dramatic move came after years of tension between Qatar and its Gulf neighbours, in particular Saudi Arabia.
German Foreign Minister Sigmar Gabriel, in an interview with Frankfurter Allgemeine Zeitung newspaper, warned that the dispute could escalate into a war.
He said there was a “dramatic harshness” in their dealings with one another, but there was still a chance to defuse tensions.
Mr Gabriel is in the region meeting the key players in the dispute.
Trump forging different path to top officials: Analysis by Barbara Plett-Usher, BBC state department correspondent
President Trump had previously tweeted support for the move to isolate Qatar over its alleged financing of extremist groups.
He repeated that message forcefully from the podium, despite US efforts to defuse the crisis: he even claimed to have been part of the decision made by Saudi Arabia and others.
Indeed, his tone and approach undercut that of Secretary Tillerson, who barely an hour earlier had delivered a more nuanced appeal for de-escalation, making clear he expected all parties to end the crisis.
While Mr Tillerson said Qatar must respond to its neighbours’ concerns, he also urged the others to take action against extremists within their borders.
US officials insisted the two men were sending the same message with different emphases, aimed at encouraging their Arab allies to put aside grievances and focus on fighting terrorism.
But it was the differences that resonated: another example, it seemed, of Trump forging a path at variance with that of his top officials.
Notably, while he criticised Qatar, he thanked Saudi Arabia. His embrace of Riyadh on a recent trip there seems to have influenced his thinking, and raised questions about the direction of any US mediation.
The tiny, oil and gas-rich Qatar strongly denies supporting Islamist extremists.
Qatar’s Sheikh Mohammed says his country has been isolated “because we are successful and progressive”, calling his country “a platform for peace not terrorism”.
Qatar’s Foreign Minister Sheikh Mohammed bin Abdulrahman al-Thani has travelled to Europe to seek support.
Russian Foreign Minister Sergei Lavrov, who met him in Moscow on Saturday, expressed concern at what he called the “sharp deterioration in the situation in the Arab world”, and said Russia would do what it could to ease the situation.
“We do not interfere in the internal affairs of other countries or their bilateral relations. But it does not give us joy when relations between our partners deteriorate,” Mr Lavrov said.
On Friday, Turkish President Recep Tayyip Erdogan said he had never known Qatar to support terrorist groups and called for the blockade to be fully lifted.
Mr Erdogan was meeting Bahrain’s foreign minister on Saturday.