Asked by reporters on a visit to Washington if the demands were non-negotiable, Saudi Foreign Minister, Adel al-Jubeir said on Tuesday: "Yes."
"We made our point, we took our steps and its up to the Qataris to amend their behaviour and once they do things will be worked out but if they dont they will remain isolated," Jubeir said.
"If Qatar wanted to return to the Gulf Cooperation Council fold, they know what they have to do," he added.
Saudi Arabia, the United Arab Emirates, Bahrain and Egypt imposed a boycott on Qatar three weeks ago, accusing it of backing militants - then issued an ultimatum, including demands it shut down a Turkish military base in Doha, shutting the Al Jazeera TV channel and curbing ties with Iran.
Qatar denies the allegations against it and says the demands are aimed at curbing its sovereignty.
US Secretary of State Rex Tillerson is scheduled to meet Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman Al Thani at the State Department on Tuesday, Reuters reported.