Israel's President Isaac Herzog has received a letter from US President Donald Trump formally urging him to fully pardon Prime Minister Benjamin Netanyahu.

Netanyahu has been standing trial for the past five years on charges of bribery, fraud and breach of trust in connection with three separate cases. He has denied any wrongdoing.

In the letter, Trump writes that he absolutely respects the independence of Israel's justice system, but that he believes Netanyahu is facing a political, unjustified prosecution.

Herzog's office said he held Trump in the highest regard, but that anyone seeking a pardon had to submit a formal request.

There was no immediate comment from Netanyahu, but he has previously thanked Trump for similar calls he has made in speeches and on social media.

In 2020, Netanyahu became the first serving Israeli prime minister to stand trial.

In the first case, prosecutors have alleged that he received gifts - mainly cigars and bottles of champagne - from powerful businessmen in exchange for favours.

He is accused in the second case of offering to help improve the circulation of an Israeli newspaper in exchange for positive coverage.

And in the third, prosecutors have alleged that he promoted regulatory decisions favourable to the controlling shareholder of an Israeli telecoms company in exchange for positive coverage by a news website.

Last month, after helping to broker the ceasefire in Israel's two-year conflict with Hamas in Gaza, Trump mentioned that Herzog should pardon his close ally, describing the case against Netanyahu as a political, unjustified prosecution.

Israel's far-right National Security Minister, Itamar Ben-Gvir, urged Herzog to listen to President Trump, citing problems with the prosecution's integrity.

However, opposition leader Yair Lapid reminded that the Israeli law stipulates that a pardon requires an admission of guilt and remorse, asserting Israel's sovereignty against perceived external pressures.

With Netanyahu's trial already a politically charged issue, the proposed pardon could further polarize opinions in the nation, especially amidst a backdrop of calls for judicial reforms that have electrified public discourse in recent years.