ISTANBUL — Saudi Arabia has agreed to reopen land, air and sea links with Qatar, de-escalating a feud that has sharply divided the Middle East for more than three years, according to the government of Kuwait, which has been mediating the dispute.

An announcement carried by Kuwait’s state news agency, citing the country’s foreign minister, said the borders and the airspace between Saudi Arabia and Qatar would reopen Monday evening. The announcement came a day before Saudi Arabia was set to host an annual summit of Persian Gulf states.

A Saudi government spokesman did not immediately respond to a request for comment. Saudi Crown Prince Mohammed bin Salman said Monday that the summit aimed at “reunification and solidarity in facing the challenges in our region,” according to the official Saudi Press Agency.

Led by Saudi Arabia, a group of Arab countries made a diplomatic break with Qatar in June 2017, accusing it of supporting terrorist groups. The countries — which included the United Arab Emirates, Egypt and Bahrain — cut links by land, sea and air, and imposed an economic blockade on Qatar. The rift was the most serious in decades among the Persian Gulf monarchies and complicated U.S. efforts to unify Arab allies against the Islamic State militant group as well as Iran, the Trump administration’s main regional adversary.

Qatar, which hosts a major base for the U.S. military’s Central Command, denied sponsoring terrorist groups. But Qatar’s support for Islamist groups in the region and its hosting of the influential Al Jazeera news channel have been sources of anguish for Saudi Arabia and its allies for years.

A senior U.S. official said that Saudi Arabia, along with the United Arab Emirates, Egypt and Bahrain, would sign an agreement ending their dispute with Qatar at the Saudi summit Tuesday. Jared Kushner, a White House senior adviser and Trump’s son-in-law, helped broker the deal, the official said.

Kushner, Middle East envoy Avi Berkowitz and Brian Hook, a special State Department adviser, are traveling to Saudi Arabia to attend the signing ceremony, which would formalize the reopening of Saudi airspace and land and sea borders with Qatar, the senior U.S. official said.

A person familiar with the negotiations said Saudi Arabia and its allies had dropped the list of 13 demands they had made of Qatar for ending the blockade. The demands had included shutting down Al Jazeera and scaling back Qatar’s cooperation with Iran.

Qatar, in turn, had agreed to freeze legal actions against the blockading states at the World Trade Organization and other institutions, said the person, who spoke on the condition of anonymity to discuss diplomatic negotiations.

The person said Saudi Arabia and the UAE had disagreed over whether to end the boycott of Qatar, with the UAE resisting the move. But Saudi Arabia “wanted to end the blockade and didn’t want to have this issue remain on its plate as the Biden administration comes into office.”

The agreement, if concluded, would end a dispute that has generated years of bombastic rhetoric by the governments involved but seemingly little popular enthusiasm. Instead, the dispute seemed only to complicate the lives of people with cross-border commercial and familial ties, as well as workers and students who hail from the boycotting countries but reside in Qatar.

It is not yet clear whether the agreement would entirely end the tensions. In the past few weeks, Qatar accused Bahrain of violating its airspace with fighter jets. Bahrain, in a letter to the United Nations Security Council, called the claim “baseless, unfortunate and unrelated to facts,” according to a statement from Bahrain’s government communications office on Dec. 26.

The letter condemned Qatar’s “continued provocative and hostile behavior, its sponsorship of terrorism and its interference in the internal affairs of neighboring countries,” the statement said.

Hudson reported from Washington.