Donald Trump has invited Israel’s prime minister and leader of the opposition to Washington for talks on the “prospects of peace”, signalling that the White House was preparing to share details of its long-awaited “ultimate deal” for Israelis and Palestinians.

Mike Pence, the US vice-president who is visiting Jerusalem for a Holocaust remembrance forum, said after a meeting with Benjamin Netanyahu that he had asked the leader to fly to Washington next week.

“President Trump asked me to extend an invitation to Prime Minister Netanyahu to come to the White House next week to discuss regional issues as well as the prospect of peace here in the Holy Land,” he said. Opposition leader Benny Gantz would also visit, he added, although it was not clear if at the same time.

No Palestinian representatives appeared to have been invited.

Trump later tweeted: “Reports about details and timing of our closely-held peace plan are purely speculative.”

But Israeli media, citing unnamed officials, reported that details of the much-delayed plan could be released as soon as this week – and that they would be extremely favourable to Israel. Reports suggested the proposal would allow Israel to retain large parts of the occupied Palestinian territories, including Jewish settlements, and all of contested Jerusalem. The Palestinians would be granted statehood, but under tight conditions and restrictions.

The timing of the reported release was widely seen as a boost for Trump’s close ally, Netanyahu, who is battling three corruption charges and faces a fierce battle as he fights for re-election in a 2 March poll. Israel’s longest-serving leader has failed to form a government after two inconclusive elections but sought to play up his acumen with Trump and other world leaders to prove to Israelis that he can score big diplomatic wins.

Speaking at the US embassy in Jerusalem, Netanyahu said the country “had no better friend than President Trump”.

“With this invitation, I think that the president is seeking to give Israel the peace and security that it deserves. So I gladly accept your invitation, his invitation, to come to Washington and discuss with him his ideas on how to advance peace and to work closely with him to advance that goal.”

He said he had asked that Gantz also be invited, as the plan would need “as broad a consensus as possible”.

The Palestinian president, Mahmoud Abbas, immediately rejected the US move.

“This step only reaffirms our absolute rejection of what the US administration has done so far, particularly the recognition of Jerusalem as Israel’s capital,” Abbas’s spokesman said in a statement.

The Palestinian leadership has pre-emptively rejected any blueprint for a deal from the Trump administration, citing a series of pro-Israeli moves made by Washington. Since he came to power, Trump has moved the US embassy to Jerusalem, shuttered the US consulate dealing with Palestinians and cut hundreds of millions in aid to the Palestinians.

Expectations are exceedingly low, even by the standards of Middle East peace plans, that the proposal will lead to an agreement. Trump first billed it as the “ultimate deal” but the process has been dogged by delays and false starts.

Trump’s son-in-law Jared Kushner is leading the project but has failed to gather much diplomatic support, while a lack of clarity around who will be Israel’s next prime minister – and the person to negotiate with – has also stalled the process. In June, Kushner held an economic conference in Bahrain, which the Palestinians said was a cheap bribe to bring them to the table.

Husam Zomlot, former head of the Palestinian mission in the US, told AFP that the invitations to two Israeli leaders and no Palestinians showed the meeting was about influencing domestic Israeli politics, rather than a genuine attempt at peace.

“This is confirmation of their policy from the beginning – it is all about and for Israel,” Zomlot said.