Mr Erekat, 65, who had been in almost every round of peace talks since the 1990s, was in critical condition after being transferred for treatment to an Israeli hospital in West Jerusalem three and a half weeks ago .
His son Ali confirmed his death on Tuesday, as did the Hadassah hospital where he was being treated. The family said he had “made a peaceful transition” to the hospital after complications from the coronavirus.
“Saeb has lived a life of reflection, love, forgiveness and peace and he will be sorely missed,” they said in a statement.
Foreign Minister Dominic Raab called Mr. Erekat “a champion of dialogue and Palestinian rights” and sent his condolences to the family and “the Palestinian people at this difficult time”.
Tony Blair hailed him as a “legendary negotiator, aware of all the intricacies and details of the” two-state solution “and a tireless advocate of it. ”
Palestinian President Mahmoud Abbas announced three days of mourning, declaring that the death of Mr. Erekat was a “great loss for Palestine and our people” especially “in light of these difficult circumstances facing the Palestinian cause”.
He added that Mr. Erekat “will be remembered as the righteous son of Palestine, who stood at the forefront of defending the causes of his homeland and his people.” Mr Abbas said the flags will be half-masted during the period of mourning.
Hanan Ashrawi, member of the PLO’s executive committee, said his death was “a significant transition in Palestinian history and reality”.
“He was firmly committed to the rights of his people, unwavering in his quest for a just peace, and totally fearless in his quest for freedom and rights,” she wrote on Twitter.
Hamas, the militant group that rules Gaza and is a rival to Erekat’s Fatah party, also sent condolences and praised its support for the Palestinian cause.
Condolences were also sent from the Israeli side.
Tzipi Livni, a former Israeli foreign minister who negotiated with Erekat in the 2000s, said she was “saddened” by his death, adding that he texted her after he fell ill, saying: ” I’m not done with what I was born to do. “
Yossi Beilin, former Israeli cabinet minister and peace negotiator, called Mr. Erekat’s death “a great loss for those who believe in peace, both on the Palestinian side and on the Israeli side.”
Mr. Erekat had undergone a lung transplant in 2017 and tested positive for Covid-19 in early October.
On October 9, he tweeted that he was suffering from “difficult symptoms”, due to the lack of immunity he had from the lung transplant. At the time, he said “things are under control, thank goodness”.
But his condition worsened, and on October 18 he was transferred from his home in the West Bank to Hadassah Bin Kerem Hospital in Jerusalem.
Soon after, his daughter Dalal said he was “fighting fiercely” against the disease.
He was then anesthetized and put on a ventilator, according to a spokesperson for Hadassah Hospital, who said the team “shares the grief of [his] family, relatives, friends and the Palestinian people ”.
British and American trained, Mr. Erekat was a seasoned peace negotiator who was involved in almost every round of peace talks between the Israelis and the Palestinians dating back three decades to the historic Madrid conference in 1991.
There he presented himself as draped in a black and white checkered keffiyeh, a symbol of Palestinian nationalism.
Two years later he helped negotiate the historic Oslo Accords in 1993. This created the Palestinian Authority and gave the Palestinians limited autonomy in the West Bank and Gaza Strip for the first time since Israel occupied the territories in 1967.
Over the next few decades, he was a staunch supporter of the Palestinian state and of a two-state solution becoming a constant presence in Western media.
He has regularly defended Palestinian leaders and accused Israel of failing to reach an agreement.
Over the past several years, Mr. Erekat has often been the public face of the war of words with the Trump administration over a US peace plan seen as the most pro-Israel vision for the region ever offered by Washington because he has gave parts of the occupied West Bank to Israel, leaving pockets of land like a Palestinian state with little sovereignty.
He remained a supporter of the negotiated creation of a Palestinian state alongside Israel even after the collapse of the peace talks and the breakdown of relations with the United States by the Palestinians two years ago.
Mr Erekat was born one of seven children in 1955 in Abu Dis, a town just outside Jerusalem and saw the Israelis take over the West Bank in the 1967 war.
In the 1970s he moved to San Francisco to attend college before completing a PhD in Peace and Conflict Studies at the University of Bradford in the UK.
He was considered a staunch supporter of the late Palestinian leader Yasser Arafat and a close aide to current President Abbas.
In the last three months of his life, Palestinians faced a tectonic shift in regional priorities when two Gulf Arab states suddenly signed agreements recognizing that Israel and Sudan formally accepted a third.
Asked a year before his death whether there was a danger of disappearing from the middle ground of Palestinian politics, Erekat told Reuters: “This is happening. These are my sons and daughters and grandchildren. And they look me in the eye and they say: did not deliver. Let the struggle change. ”
But he was adamant that in the long run, his vision would prevail. “The idea of the two-state solution will never die,” he said. “There is no other option. “
Agencies contributed to this report