US President Donald Trump’s Special Envoy for International Negotiations Jason Greenblatt has “unequivocally” stressed that the White House is striving to achieve a peace deal between Israel and the Palestinians, the Zionist Union leader Isaac Herzog said Saturday.

“Trump’s envoy to the Middle East told me unequivocally that the president of the United States is determined to reach an agreement between us and the Palestinians,” Herzog said during an event in the central Israeli city of Rishon Lezion.

The Labor leader dubbed Trump’s upcoming visit to Israel as a “tiebreaker,” adding that it was now up to Prime Minister Benjamin Netanyahu to decide whether to cooperate with the Trump administration to try to reach a deal.

“Netanyahu has to decide whether he is working for the people of Israel or working for [Coalition chairman David] Bitan and [Culture Minister Miri] Regev,” Herzog said, referring to two Likud MKs with a hawkish stance on matters concerning the Palestinians.

Herzog promised opposition support if Netanyahu, who heads a multi-party coalition, does attempt to make substantive progress with the Palestinians.

Trump’s incoming Ambassador to Israel David Friedman also told Israeli diplomats that is intent on reaching a peace deal, and urged them to cooperate and aid the president in his endeavor, Haaretz reported Friday. An Israeli government source told the newspaper that Friedman claimed Trump’s enthusiasm for relaunching the peace process presented a great opportunity for the Jewish state, and advised officials to avoid confrontation with the president over the matter. However, Friedman has also advised Trump that the prospects of achieving peace at present are low, two people who spoke with the envoy said.

US Middle East envoy Jason Greenblatt meets Palestinian Authority President Mahmoud Abbas on the sidelines of the Arab League Summit in Amman, March 28, 2017 (Wafa/Thair Ghnaim)

US Middle East envoy Jason Greenblatt meets Palestinian Authority President Mahmoud Abbas on the sidelines of the Arab League Summit in Amman, March 28, 2017 (Wafa/Thair Ghnaim)

On Friday, US National Security Adviser H.R. McMaster told reporters during a daily press briefing in Washington that Trump will work toward a “just and lasting peace” between Israel and the Palestinians on his upcoming trip to the region. McMaster added that that Trump will meet again with Palestinian Authority President Mahmoud Abbas, and will “express his desire for dignity and self-determination for the Palestinians.”

The White House official also said that Trump’s meetings with Israeli leaders would look to cement stronger ties between the two allies.

US President Donald Trump, right, Prime Minister Benjamin Netanyahu shake hands during a joint press conference in the East Room of the White House, in Washington, DC, February 15, 2017. (AFP PHOTO / MANDEL NGAN)

US President Donald Trump, right, Prime Minister Benjamin Netanyahu shake hands during a joint press conference in the East Room of the White House, in Washington, DC, February 15, 2017. (AFP PHOTO / MANDEL NGAN)

“With President [Reuven] Rivlin and Prime Minister Netanyahu, he will reaffirm America’s unshakable bond to the Jewish state,” he said.

Throughout the trip, Trump will “demonstrate his hopes for a just and lasting peace,” McMaster added.

Trump’s visit to Israel, which was officially announced last week, will take place from May 22 to 23 — just before Jerusalem Day — after he stops in Saudi Arabia and before he goes on to the Vatican. He will also travel to Brussels and Sicily for NATO and G7 summits on the final leg of his first foreign trip.

There has been speculation since Trump’s travel plans were announced that he would seek to facilitate a trilateral meeting with Netanyahu and Abbas.

When McMaster was asked if such a plan was in the works, he demurred. “It will be up to the president and those leaders,” he said.

Trump has already hosted both Netanyahu and Abbas at the White House, expressing optimism in his ability to succeed in brokering a peace deal where his three immediate predecessors have failed.

“It’s something that I think is, frankly, maybe not as difficult as people have thought over the years,” Trump told Abbas during their joint press conference. “We need two willing parties. We believe Israel is willing. We believe you’re willing. And if you are willing, we are going to make a deal.”

Abbas reportedly showed Trump maps drawn up as part of a former Israeli prime minister’s 2008 peace proposal, which Abbas chose not to accept at the time, during his visit to the White House last week.

US President Donald Trump meets with Palestinian Authority President Mahmoud Abbas in the Oval Office of the White House on May 3, 2017 in Washington, DC. (AFP/MANDEL NGAN)

US President Donald Trump meets with Palestinian Authority President Mahmoud Abbas in the Oval Office of the White House on May 3, 2017 in Washington, DC. (AFP/MANDEL NGAN)

He also reportedly told Trump that his negotiations with former Israeli prime minister Ehud Olmert, which fell apart without an agreement, should form the basis of any future peace talks.

The PA leader ultimately balked at Olmert’s 2008 offer, and later cited the then-prime minister’s legal troubles at the time as his primary reason. Olmert had announced that he planned to resign in order to fight corruption allegations, and Abbas doubted the Israeli had the political clout to see the deal through. Olmert is currently serving a 26-month jail sentence on various corruption charges.

After last week’s summit between Trump and Abbas, Likud Minister Ze’ev Elkin said that although it was likely peace talks would resume, it was unlikely a deal would be reached soon.

Elkin noted Abbas’s intransigence in 2009 and 2010, during which Israel, under Netanyahu, instituted a ten-month settlement freeze that the PA president had demanded.

At that time, talks also broke down with the Palestinians arguing that the construction halt was merely partial as it did not include a suspension on building in East Jerusalem. Israel claims sovereignty throughout Jerusalem ad does not regard construction in parts of the city captured in the 1967 war as settlement building.

The Hamas terror group, which rules the Gaza Strip, has been quick to reject any proposed negotiations between Israelis and Palestinians, stating that Abbas has no mandate.