Israeli Prime Minister Ehud Olmert has called on President Moshe Katsav to resign over allegations of rape and abuse of power.
It comes after Mr Katsav strongly denied the accusations but vowed to step down if he was formally charged.
In an emotionally-charged news conference, Mr Katsav said he would fight to clear his name, "even if it means a world war".
He has asked the speaker of parliament to grant him temporary leave.
Attorney General Meni Mazuz said on Tuesday that he intended to charge Mr Katsav with offences including rape, obstruction of justice and fraud.
The president, who has not yet been legally indicted, is under increasing pressure from ministers and MPs to step down.
A formal indictment might only be filed after a special hearing between his legal team and state prosecutors, which could take several weeks.
Speaking in the northern town of Herzliyah, Mr Olmert called on Mr Katsav to quit.
"Under these circumstances, there is no doubt in my mind that the president cannot continue to fulfil his position and he must leave the president's residence," he said.
His comments followed a nationally televised news conference in which a visibly angry Mr Katsav denied the accusations against him.
At one point the president railed against a reporter from Israel's Channel 2 television, accusing it of leading a campaign against him.
He implored the public not to believe the allegations, saying: "When the truth comes out you will be shocked."
"Don't believe the libel, the defamation, the lies," he said. "There is only one truth... I am the target of one of the worst attacks in the history of the State of Israel."
Mr Katsav vowed to stay in office to fight the allegations.
"The law does not oblige me to resign," he said. "I will not give in to blackmail."
Mr Katsav has requested temporary leave of absence, during which the speaker of the Knesset (parliament) will act in his place.
A parliamentary committee would have to approve such a move.
The BBC's Rachel Harvey in Jerusalem says as long as Mr Katsav retains the title of president he still has immunity from criminal prosecution.
Mr Katsav's seven-year term ends later this year.
Some 30 members of the Knesset have signed a petition to begin moves to have Mr Katsav impeached, Israeli media reported.
The accusations, brought by four women, date back several years.
If the case does go to trial and if he is found guilty, Mr Katsav could face up to 16 years in prison.