Political parties opposing Israeli Prime Minister Benjamin Netanyahu could announce a coalition to oust the long-time leader as early as Sunday, Israeli media reported.
After four inconclusive parliamentary elections in two years, a 28-day mandate for opposition leader Yair Lapid – who runs the centrist Yesh Atid party – to form a new government runs out on Wednesday. Mr Lapid is believed to be teaming up with Naftali Bennett, whose right-wing Yamina party has six seats in Parliament.
The new "change" bloc would include parties from the right and left and would include a rotational prime-ministerial role shared between Mr Lapid and Mr Bennett.
Still short of a parliamentary majority after a March 23 election that ended in stalemate, such a diverse grouping could be fragile and would require outside backing from Arab members of parliament whose political views differ sharply from Yamina's.
Mr Netanyahu further fuelled speculation on Friday that his own tenure was about to end with a tweet and video warning that a dangerous "left-wing" administration was on the cards.
Israel's longest-serving prime minister, Mr Netanyahu's current term began in 2009. He previously served in the role between 1996 and 1999.
Yamina announced late on Saturday that Mr Bennett would meet and update its legislators on Sunday, after reports he had agreed to a deal in which he would serve as prime minister first, before handing over to centrist Mr Lapid.
Although the Lapid-Bennett agreement was reportedly finalised before the Israeli bombardment on Gaza began on May 10, Mr Bennett said during the hostilities that he was abandoning efforts to form a coalition with the centre and left.
But a ceasefire has so far held, a recent wave of street violence in Israel between Arabs and Jews has ebbed, and the partnership could be back on course.
Israeli political commentators, however, were taking nothing for granted.
"The anti-Prime Minister Benjamin Netanyahu government of change is still not an accomplished fact," political columnist Yossi Verter wrote in the left-wing Haaretz newspaper on Sunday.
"It's premature to pop open the champagne, and also too early to wear sackcloth," he said, questioning whether Yamina's politicians could withstand pressure from the right against a deal with Mr Lapid.
If Mr Lapid, 57, fails to announce a government by Wednesday, a fifth Israeli election since April 2019 – a prospect Mr Bennett has said he wants to avoid – is likely.