Saudi Arabia has re-established diplomatic relations with Qatar, more than three years after Riyadh and several Arab countries severed ties with Doha.

This comes as Saudi Arabia announces that it will reopen its air, 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 controversy erupted in 2017. He was there to attend the annual Gulf Cooperation Council summit in the ancient city of Al-Ula.

Relations between the Arab world increased in 2017 when Saudi Arabia and its allies, the United Arab Emirates, Bahrain and Egypt imposed a diplomatic, trade and travel embargo on Qatar. They accused the small Gulf country of supporting terrorism and being too close to Iran, which Doha has always denied.

The controversy plunged the country into an unprecedented diplomatic crisis after the 1991 war against Iraq, exposing deeper ideological differences in the region.

Al Thani said in 2018 This controversy is a “useless crisis” Qatar defended its sovereignty despite “aggression” from neighboring countries.

Al-Arabiya, a Saudi-owned media outlet, also reported on Tuesday that Egypt had agreed to reopen its airspace to Qatar.

Ahead of the summit, UAE Foreign Minister Anwar Karkash said in a tweet that the GCC meeting would restore Gulf unity. He added: “There is still work to be done. We are on the right track.”

The resumption of diplomatic relations between Saudi Arabia and Qatar is part of Washington’s latest bid for brokerage deals in the Middle East. In the diplomatic victory for President Donald Trump, the United Arab Emirates, Bahrain, Sudan and Morocco normalized relations with Israel in 2020.

The Turkish Foreign Ministry on Monday welcomed the reopening of borders between Qatar and Saudi Arabia.

“Our hope is that a comprehensive and lasting solution to this conflict will be reached on the basis of mutual respect for the sovereignty of all nations and that all other sanctions against the Qatari people will soon be lifted.” The ministry said in a statement.

– CNBC’s Ryan Brown and Mila Ladouff contributed to this report.