WASHINGTON (Reuters) - Jason Greenblatt, President Donald Trump’s special envoy for the Middle East, plans to resign once the long-delayed U.S. peace plan for Israel and the Palestinians that he has been working on is released, officials said on Thursday.

FILE PHOTO: Jason Greenblatt (C), U.S. President Donald Trump's Middle East envoy, arrives to visit Kibbutz Nahal Oz, just outside the Gaza Strip, in southern Israel August 30, 2017. REUTERS/Amir Cohen/File Photo

Greenblatt, who had intended to stay only two years when he began working at the White House in early 2017, is eager to return to his wife and six children who stayed behind at their home in New Jersey, the officials said.

Greenblatt and White House senior adviser Jared Kushner, as well as the U.S. Ambassador to Israel, David Friedman, have led the effort to develop a peace plan for Israel and the Palestinians and have spent the entire Trump presidency working on the project.

Described by Trump as the “deal of the century,” the Republican president’s plan to solve one of the world’s most intractable disputes has drawn deep scepticism from Palestinians.

Trump called Greenblatt “a loyal and great friend and fantastic lawyer” and said he would be leaving to pursue work in the private sector. “His dedication to Israel and to seeking peace between Israel and the Palestinians won’t be forgotten,” Trump said in a Twitter post.

So far, the White House has outlined a $50 billion redevelopment plan for the Palestinians and neighbouring countries but have yet to release their proposals for resolving difficult political issues like the status of Jerusalem.

U.S. officials said the political plan is now complete and will be made public when appropriate. Trump has said he will release it some time after Israel holds an election on Sept. 17 that will decide the fate of Prime Minister Benjamin Netanyahu.

Whether Trump releases the plan immediately after the election or he waits until a governing coalition is formed, a process that could take weeks, remains unclear.

PALESTINIAN BOYCOTT

The Palestinian Authority has boycotted the U.S. peace effort since late 2017 when Trump decided to move the U.S. Embassy from Tel Aviv to Jerusalem and recognised Jerusalem as the capital of Israel, reversing decades of U.S. policy.

The Palestinian Authority declined to comment on Greenblatt’s departure. “Greenblatt’s resignation is proof of his failure, because he did not follow the rules of the peace process and damaged the United States’ credibility as a result,” a Palestinian official in Ramallah told Reuters.

The political details of the plan have remained under wraps, with Kushner refusing to say even whether it would offer Palestinians a state of their own.

Greenblatt will hand over much of his Middle East responsibilities to Kushner aide Avi Berkowitz. Brian Hook, the leader of the State Department’s Iran team, will take on an increased role, a senior administration official said.

Hook has accompanied Greenblatt and Kushner on trips to the region. In a July statement, Greenblatt and Hook argued that Tehran has exploited the Mideast conflict for decades, backing Palestinian militants.

Greenblatt, a former lawyer for Trump, said he was grateful to have been part of the team to draft “a vision for peace.”

“This vision has the potential to vastly improve the lives of millions of Israelis, Palestinians and others in the region,” he said in a statement.

Greenblatt has been a player in all of Trump’s moves aimed at bolstering support for Israel, such as the U.S. recognition of both Jerusalem as the capital of Israel and Israeli sovereignty over the Golan Heights.

The developing peace plan, which Greenblatt and others have kept secret, is viewed sceptically among many in the Arab world because of expectations it will be a pro-Israel vision. The U.S. team says the plan will require concessions from the Israelis.

Kushner, in a statement, said Greenblatt “has done a tremendous job leading the efforts to develop an economic and political vision for a long sought after peace in the Middle East.”