Jerusalem (CNN) Israeli Prime Minister Benjamin Netanyahu will be indicted on bribery and breach of trust charges arising from three separate corruption investigations, pending a hearing, Israel's attorney general announced Thursday evening.

The announcement, so close to April's general election, marks a dramatic moment in Israeli politics and is a major blow to Netanyahu as he seeks a fifth term in office.

He has repeatedly denied any wrongdoing, denouncing the investigations as a media-led witch hunt. In a prime time broadcast shortly after the announcement, Netanyahu blamed the left for pressuring Attorney General Avichai Mandelblit -- a Netanyahu appointee -- to issue an indictment.

"The left understands that they will not beat me at the ballot box," Netanyahu said. "They exerted extraordinary pressure on the attorney general to issue an indictment even though there is nothing, in order to influence the elections and to crown a left-wing government."

"This entire house of cards will collapse. I am sure of it 4,000%," he added, referencing one of the cases against him.

Netanyahu is entitled to a hearing on the impending indictment before charges are formally laid, but that is not expected to take place until long after the election. Under Israeli law, Netanyahu is not required to step down if he is indicted. He is only required to step down if he is convicted and that conviction is upheld through the appeals process, which could take years.

Netanyahu's main challenger in the upcoming elections, former military Chief of Staff Benny Gantz, called on him to resign after the attorney general's announcement.

"Because of the circumstances which have arisen, sitting [in a future government] with Benjamin Netanyahu is not something which is on the table," Gantz said Thursday evening in response to Netanyahu's statement.

"Benjamin Netanyahu -- I turn to you this evening. Get over yourself and show national responsibility. Resign from your position. If you prove that you are innocent, you can return to the public realm and again lead your movement," Gantz added.

Thursday's developments cloud an already murky Israeli political landscape. Netanyahu's political enemies will use the investigations against him, but his coalition partners must now decide whether to support a leader who is likely to be indicted or withdraw support and risk angering their shared right-wing voter base.

So far, key right-wing coalition partners have said they will still support Netanyahu, because he is presumed innocent until proven guilty.

Cigars, champagne, and corruption claims

In the first case, known as Case 1000, Mandelblit intends to charge Netanyahu with breach of trust. Case 1000 deals with alleged gifts Netanyahu received from overseas billionaires totaling 1 million shekels (approximately $280,000), including cigars, champagne, jewelry and more. The alleged transfers occurred between 2007 and 2016. In exchange for the gifts, investigators say Netanyahu tried to advance a tax break that would have benefited the businessmen.

In another case, known as Case 2000, Mandelblit plans to charge Netanyahu with another count of breach of trust. Case 2000 deals with alleged negotiations between Netanyahu and Arnon "Noni" Mozes, the owner of one of Israel's largest newspapers, Yedioth Ahronoth. Investigators say Netanyahu requested more favorable coverage in exchange for limiting the circulation of Yedioth Ahronoth's largest rival, Israel HaYom, a free daily owned by right-wing mega-donor Sheldon Adelson that is viewed by critics as a Netanyahu mouthpiece.

The attorney general also announced his intention to indict Mozes with bribery. Mozes' lawyer has said his client is innocent and he expects the cases to be closed without charges being filed.

In another case, known as Case 4000, Netanyahu faces bribery and breach of trust charges. This case is arguably the largest facing the Prime Minister. It deals with the relationship between Netanyahu and Israeli telecommunications firm Bezeq. Investigators say Netanyahu advanced regulatory benefits worth 1 billion shekels (approximately $280 million) to the company and its primary shareholder, Shaul Elovitch, a friend of Netanyahu. Along with holding the position of Prime Minister, Netanyahu also served as the minister of communications at the time. In exchange for the benefits, the case alleges Netanyahu received favorable news coverage from Walla News!, an online news organization owned by Elovitch.

Mandelblit said he intended to indict Elovitch with bribery, pending a hearing. Like Netanyahu, Elovitch has denied any wrongdoing.

Netanyahu and his high-powered legal team have repeatedly argued that any statement from the attorney general about the Prime Minister's legal status should be delayed until after the elections on April 9. Such a statement could affect the outcome of the elections, they argued, with some of Netanyahu's key political allies saying it could result in an "undemocratic" change in government.

Amir Fuchs, head of the Defending Democratic Values program at the Israel Democracy Institute, said the public has the right to know as soon as possible if there is a suspicion of criminal activity against a Prime Minister.

"I think that if we are past the point that the attorney general has his decision about a draft indictment, the people have a right to know," said Fuchs. "Even a final decision by the attorney general is still not saying Netanyahu is convicted, it's just a decision by the prosecution."

Once criticized as too close to Netanyahu, Mandelblit has become the biggest thorn in the Prime Minister's side. Netanyahu's allies have attacked the attorney general, saying he spreads "gossip," as well as questioning his behavior and his decision-making.

Netanyahu rails against charges

Netanyahu has turned the investigations into a key election campaign issue, railing against the probes and denouncing them as a tool of the media and the left wing to try to topple his proudly right-wing government. In public statements, live broadcasts, and on social media, Netanyahu has sought to delegitimize them ahead of the attorney general's decision.

In mid-February, Netanyahu called Case 4000 a "fabricated case" in one tweet, and followed that up hours later with another tweet.

"It is unfortunate that the pressure of the left and the media will probably cause the attorney general to rush and to announce a hearing before the elections," he wrote.

מצער שהלחץ של השמאל והתקשורת כנראה גורם ליועמ"ש להיחפז ולהודיע על שימוע לפני הבחירות, בשעה שהאמת תצא לאור בתהליך השימוע רק אחרי הבחירות.



צר לי שהיועמ"ש דחה את בקשתי להתעמת עם עדי המדינה וגם את בקשת פרקליטיי לחקור עשרות עדים שלא נחקרו ושמוכיחים את צדקתי — Benjamin Netanyahu (@netanyahu) February 13, 2019

Political science professor Avraham Diskin reckons the Prime Minister had no real choice. "Netanyahu of course put that main issue on the table because he cannot avoid the elephant in the room."

"He might crack," Diskin went on, "[but] there are no signs for that yet, and if he doesn't crack, I think that he is following a reasonable strategy."

Netanyahu's main rival, Gantz, the former IDF chief of staff, has turned the investigations into one of his main weapons.

In his first major speech as a candidate in February, Gantz said unequivocally, "The very thought that a prime minister can serve in Israel with an indictment is ridiculous to me. This cannot happen." Many other politicians have also hammered Netanyahu on the investigations, but the attacks have done little to erode the steadfast support of his base.

Netanyahu's Likud party has consistently polled right around the 30 seats he currently has, but some polls have Likud losing seats.

Not the only Netanyahu in legal hot water

Netanyahu's wife, Sara, faces corruption charges of her own, in a separate case. She was charged last summer with fraud after an investigation in which prosecutors say she misused taxpayer dollars at the Prime Minister's official residence between 2009 and 2013.

She is accused of inappropriately using state money to pay for $100,000 worth of catered meals, while also spending thousands of dollars on private chefs. Under Israeli law, it is illegal to order food to the official residence if there is already a cook employed there.

Sara Netanyahu's trial opened in October and it is not clear when it might end. Proceedings have been drawn out by attempts to reach a plea agreement.

Her lawyers have denounced the charges as "false and hallucinatory."

The beginning of the end?

The attorney general's announcement complicates Netanyahu's path to a fifth term as Prime Minister.

Support for Netanyahu's Likud party has not flagged in the face of the ongoing investigations, but a merger between his two main rivals has put his party in second place in recent polls.

Even so, political analysts say Netanyahu has the best chance of forming a government and remaining Prime Minister after the elections.

"We know that people stick to their political affiliation," Diskin said. "Here we're talking about right versus left, and for those on the left, an indictment will just be more proof that Netanyahu is a corrupt person. For those on the right, an indictment is just more proof that the Prime Minister is persecuted by all kinds of elites."

"The main question concerns the few people who are not really committed to either camp," said Diskin, estimating that undecided voters make up no more than 10% of the electorate.

"We don't know anything about them," he said, but they have the power to decide an election. Even a small shift of seats from Netanyahu to his main challenger could seriously damage Netanyahu's chances of putting together a government.

Crucially, Netanyahu cannot serve as Prime Minister without the support of his coalition partners.

Before the election was called, opposition parties had called on coalition leaders to withdraw support for Netanyahu if he was charged.

Now those coalition leaders will have to see if the attorney general's announcement changes their calculation. If they support Netanyahu and he goes down, their fate may be tied to his. But if they withdraw that support now, their collective right wing voter base could punish them in the upcoming elections.