Benjamin Netanyahu's days as Israeli prime minister could be numbered after nationalist Naftali Bennett said he would join a coalition being put together by opposition leader Yair Lapid.
Mr Bennett said his Yamina party would join a diverse collection of opponents seeking to topple Mr Netanyahu.
“It’s my intention to do my utmost in order to form a national unity government along with my friend Yair Lapid, so that, God willing, together we can save the country from a tailspin and return Israel to its course,” Mr Bennett said.
Yamina will lend six seats to Mr Lapid's effort to form a majority in the 120-member Knesset.
Mr Lapid’s centrist Yesh Atid party came second in the latest election two months ago, the fourth inconclusive poll in two years. He was given a 28-day mandate, ending on June 2, to form a government.
The negotiations were stalled by the 11-day conflict between Israel and militant groups in Gaza.
Yamina’s support is a significant milestone on the journey to oust Mr Netanyahu, who is Israel’s longest-serving prime minister. His current term began in 2009 and before that he held the post between 1996 and 1999.
The new coalition is so far made up of right-wing, centrist and leftist parties. All parties have cited the corruption charges faced by Mr Netanyahu as the main reason Israel needs a new leader.
In comments made immediately after Mr Bennett's press conference, Mr Netanyahu accused his former protege of carrying out the "scam of the century", saying he only cared about becoming prime minister. He added that the new coalition would weaken Israel and insisted a right-wing coalition was still possible.
Mr Netanyahu denies the charges, but his rivals argue that he might use a new term to legislate immunity to shield himself.
Mr Bennett, a former defence minister and ally of Mr Netanyahu, said the broad coalition would need to work together to succeed.
Everyone “will need to postpone fulfilling all their dreams. We will focus on what can be done, instead of fighting all day on what’s impossible," he said.
Mr Bennett, 49, told his party earlier in the day the new coalition would be a "government of change".
Most Israeli media predicted Mr Bennett would agree to a deal under which he would replace Mr Netanyahu and later give way to Mr Lapid in a rotation agreement.
The new coalition is expected to focus on the economic recovery from the Covid-19 pandemic, while setting aside issues on which its members disagree, such as the role of religion in society and Palestinian aspirations for statehood.
Mr Netanyahu made several attempts on Sunday to stand aside in favour of another right-wing politician, Gideon Saar, but to no avail.
Mr Saar, a former Likud Cabinet minister, swiftly rejected the offer, writing on Twitter: "Our position and commitment are unchanged – to end Netanyahu's rule."
He referred to Mr Netanyahu's "failure" to end the Hamas rule in Gaza as one of his main reasons to rally against him.
"Continued failure for 12 years in the policy vis-à-vis Gaza is registered in his name – promised in 2009 to topple the Hamas regime in Gaza," he wrote.