Arab political leaders in Israel have rejected prime minister Benjamin Netanyahu's apology for comments he made in last week's national elections that offended members of the Arab community.
They said his words made him unsuitable to return for a third consecutive term in office.
The spat has touched on long-standing claims of discrimination by Israel's Arab minority, which makes up 20% of the Jewish state, and signalled that the rift will not be healed any time soon.
An Arab advocacy centre in Israel said the country's national elections brought an "unprecedented level of racist incitement" against the minority community.
In the heat of a close race last week, Mr Netanyahu posted a video on his Facebook page where he implored his hard-line supporters to get voting, saying that "left-wing organisations" were bussing Arabs to the polls "in droves".
The comments drew accusations of racism from Arab voters and a White House rebuke.
Mr Netanyahu told a gathering of Arab dignitaries: "I know that what I said a few days ago offended some of Israel's citizens, offended Israeli Arabs. I had no intention of doing so. I am sorry for this."
But Arab politicians from the Joint List - a new coalition of mostly Arab parties - said they were not invited to the gathering at the prime minister's residence.
Ayman Odeh, head of the Joint List, said: "Why didn't he call us? Why didn't he invite us?"
There was no immediate comment from Mr Netanyahu's Likud party.
Arab politicians said his election victory was illegitimate, claiming Mr Netanyahu won the vote by pandering to anti-Arab fears.
"We call on Netanyahu to return the mandate he received on the basis of incitement and fear-mongering," the Joint List said in a statement.
The Israeli PM has secured a majority of backers in the new parliament and is expected to be formally approved on Wednesday to form the next government.
Opinion polls conducted on the eve of elections showed Mr Netanyahu's conservative Likud party trailing behind his main challenger, the centre-left Zionist Union.
His sudden turnaround victory came as Mr Netanyahu made his remark about Arab voters in the final hours of voting.
His comments on Arabs, along with a declaration that he would not allow the establishment of a Palestinian state on his watch, have infuriated the White House. His attempts to backtrack on both positions have been greeted with scepticism.
"We just don't know what to believe at this point," State Department spokeswoman Marie Harf said Monday.
The controversy comes amid the backdrop of the Arab-Israeli community's new-found political might.
The Joint List made unprecedented gains in the March 17 election, earning enough votes to make it the third-largest party in Israel's 120-seat parliament.
The Joint List said election results showed that more than 90% of Arab-Israeli voters supported the coalition in the elections.
Arab-Israeli politician Ahmed Tibi told Israel Radio Tuesday that Netanyahu's attempt to defuse the dispute was "not an honest apology".
Emilie Moatti, a spokeswoman for the Joint List, said the Arab dignitaries who gathered at Netanyahu's home were all Likud supporters, with no Joint List representatives invited.
Adalah, a legal advocacy center for Arab-Israelis, said there has been a series of attempts in recent years by Israeli politicians to delegitimise Arab citizens.
The outgoing government amended a law making it more difficult for smaller parties to enter the parliament, it said, while Likud and another hawkish party unsuccessfully filed motions to disqualify a firebrand Arab politician from running in elections. Adalah added that a wide range of parties made negative statements about Arabs in their election campaigns.
"Regardless of the debates that will unfold in the follow-up to this election, it is clear that racism was the most victorious ballot," Adalah said.