The United States government has responded to Senate pressure by pledging that it is going to offer its “largest ever” military aid package to Israel.

“We are prepared to sign an MOU (Memorandum of Understanding) with Israel that would constitute the largest single pledge of military assistance to any country in US history,” Reuters quoted a White House official as saying on Tuesday.

The statement came in response to a bipartisan letter by 83 US senators to President Barack Obama, urging him to address Israeli demands for more military assistance.

"In light of Israel's dramatically rising defense challenges, we stand ready to support a substantially enhanced new long-term agreement to help provide Israel the resources it requires to defend itself and preserve its qualitative military edge," said the letter which stopped short of suggesting a specific figure.

The lawmakers were led by Republican Senator Lindsey Graham and Democratic Senator Chris Coon. Texas Senator Ted Cruz, who is a 2016 presidential candidate, was among the 51 Republican lawmakers who signed the letter.

However, Vermont Senator Bernie Sanders, who is challenging former Secretary of State Hillary Clinton in the presidential race, refused to be one of the 32 Democrats on board.

The US and Israel have been engaged in intense negotiations in recent months to outline US military aid to Israel for the next 10 years.

Washington has been providing the Israeli regime with $3.1 billion annually since a 2007 agreement with the George W. Bush administration.

Tel Aviv has indicated that it wants $4 billion to $4.5 billion in aid as part of a new agreement that will go into effect from 2018, but the US officials have offered a lower figure of about $3.7 billion.

Israeli Prime Minister Benjamin Netanyahu is seeking to finalize the deal with Obama before the end of his presidency, fearing that his successor would take a different position on the matter.

Israel is the largest cumulative recipient of US foreign assistance since World War II. US military assistance to Israel has amounted to $124.3 billion since it began in 1962, according to a recent congressional report.