Journalists watch the screen as Saudi Crown Prince Mohammed bin Salman welcomes the Emir of Qatar, Tamim bin Hamad Al-Thani, ahead of the 41st Gulf Cooperation Council summit in the city of Al-Ula in Saudi Arabia on Jan. 5, 2021.Fayez Nureldine | AFP | Getty ImagesSaudi Arabia has reinstated diplomatic relations with Qatar, more than three years after Riyadh and several Arab countries severed ties with Doha.It comes as Kuwait, a mediator for both sides, announced that Saudi Arabia is reopening its airspace, sea and land borders with Qatar.Qatar’s emir, Sheikh Tamim bin Hamad al-Thani, arrived in Saudi Arabia on Tuesday for the first time since the dispute erupted in 2017. He was there to attend the annual Gulf Cooperation Council summit in the ancient city of Al-Ula.Relations among the Arab nations soured in 2017, when Saudi Arabia and its allies — the United Arab Emirates, Bahrain and Egypt — imposed a diplomatic, trade and travel blockade on Qatar. They accused the tiny Gulf nation of supporting terrorism and of being too close to Iran, allegations that Doha has always denied.The dispute plunged the region into a diplomatic crisis not seen since the 1991 war against Iraq, and exposed deep ideological differences in the region.Al-Thani in 2018 said the dispute was a “futile crisis,” and that Qatar preserved its sovereignty despite “aggression” from its neighbors.Saudi-owned media Al-Arabiya also reported on Tuesday that Egypt has agreed to reopen its airspace to Qatar.Ahead of the summit, the UAE’s Minister of State for Foreign Affairs, Anwar Gargash, said in a tweet the GCC meeting will restore Gulf cohesion. He added: “There is still work to be done and we are in the right direction.”Restoring diplomatic ties between Saudi Arabia and Qatar is part of Washington’s latest effort to broker deals in the Middle East. In a diplomatic win for President Donald Trump, the UAE, Bahrain, Sudan and Morocco normalized relations with Israel in 2020.Turkey’s ministry of foreign affairs on Monday welcomed the reopening of borders between Qatar and Saudi Arabia.”It is our hope that a comprehensive and lasting solution to this conflict will be reached on the basis of mutual respect to sovereignty of all countries and that all other sanctions against the Qatari people will be lifted as soon as possible,” the ministry said in a press release.— CNBC’s Ryan Browne and Mila Latoof contributed to this report.