He rarely ever publicly criticizes his successor, Barack Obama. But on Saturday night, George W. Bush apparently lashed out at the President's foreign policy. Speaking at a closed-door meeting with Jewish donors in Las Vegas,  the 68-year-old former leader suggested that Obama's plan to lift sanctions on Iran was not plausible - and comes too early. He noted that the country's government and President Hassan Rouhani appear to be caving in - and implied that America could lose leverage if it relaxes sanctions on Tehran anytime soon. And he said that the comprehensive nuclear deal - which is currently being negotiated by six global powers, including the US - would likely have a negative impact on US national security in the future. Scroll down for video . Rare remarks: Speaking at a  meeting with Jewish donors in Las Vegas, George W Bush (pictured) suggested that President Barack Obama's plan to lift sanctions on Iran was not plausible - and comes too early . 'You think the Middle East is chaotic now? Imagine what it looks like for our grandchildren. That’s how Americans should view the deal,' Bush told donors at the Republican Jewish Coalition session. Bush's concerns are in stark contrast to Obama's belief that although the contents of the agreement - which were announced at the start of April - 'may not be optimal,' they are America's 'best bet'. In an interview with the New York Times, Obama remarked: 'This is our best bet by far to make sure Iran doesn’t get a nuclear weapon.' But he noted the deal could see 'real political difficulties'. Bush's administration initially began the diplomatic effort to confront the Iranian regime about its nuclear program. He also made attempts early in his administration to negotiate with North Korea. During his comments on Saturday, transcribed by an attendee at the event at the Venetian Hotel and obtained by Bloomberg, the former president told donors that he would not criticize Obama. He congratulated his successor on his ambition to degrade and destroy the Islamic State, which has taken over large swathes of Iraq and Syria and beheaded US journalists on video last year. Leaders: Bush, who rarely ever publicly criticizes Obama, noted that the Iranian government and President Hassan Rouhani appear to be caving in. Above, Bush, left, greets Obama in Selma, Alabama, in March . Terror group: Bush initially congratulated his successor on his aim to degrade and destroy the Islamic State. But he went on to imply that Obama has failed to keep his promises and is losing the war against the group . But he then went on to suggest that Obama had failed to follow through on his promises, saying that one of the key issues was that the Democrat did not develop a military strategy to defeat the terror group. 'In order to be an effective president ... when you say something you have to mean it,' he said, according to Bloomberg, implying that Obama is losing the war against ISIS. 'You gotta kill em.' Bush even reportedly touted his own success in capturing Islamic terrorist Khalid Sheikh Mohammed, who murdered Wall Street Journal reporter Daniel Pearl and countless others. In relation to Obama's decision to withdraw all American troops from Iraq in 2011, Bush cited Senator Lindsey Graham, of South Carolina, who has publicly criticized the President's foreign policy. He quoted him as saying: 'Pulling out of Iraq was a strategic blunder,' according to theNew York Times, which collected accounts of Bush's comments from around 12 people at the session. A dangerous last name? Bush apparently remarked that his brother, presidential candidate Jeb Bush (above) could encounter struggles in his campaign due to his last name because Americans do not like dynasties . Bush's comments followed an interview with CBS News last November in which he suggested that the draw down of troops in the war-torn country had allowed ISIS to flourish and recruit more militants. Speaking to news station in a two-part interview, the politician said he thought it was 'the right decision' to take military action in 2003 in a bid to oust Saddam Hussein. But he added: 'My regret is that…a violent group of people have risen up again…This is "Al-Qaeda plus"…they need to be defeated. And I hope we do…I hope the strategy works.' During Saturday's question-and-answer session, Bush also told anecdotes about his old friend, Russian President Vladimir Putin, whom he said had once told him that his dog was 'bigger, stronger and faster' than Bush's own. Bush considered the  comparison to show Putin did not think in 'win-win' terms, he said. He also apparently remarked that his  brother, presidential candidate Jeb Bush, could encounter struggles in his campaign due to his last name because Americans do not like dynasties. And he called Hillary Rodham Clinton 'formidable', but beatable, the Times reported. The session was attended by Republican donor Sheldon Adelson, who owns the Venetian hotel. It comes as U.S. Secretary of State John Kerry is due to meet with Iranian Foreign Minister Mohammad Javad Zarif in New York on Monday, according to a senior State Department official. Kerry, who will be participating in a nuclear non-proliferation conference that opens at the United Nations on Monday, will also apparently meet with Jordanian Foreign Minister Nasser Judeh. And he will spend time with Egyptian Foreign Minister Sameh Shoukry, the official said.
Bush, 68, implied Obama's plan to lift sanctions on Iran comes too early . He noted that Islamic country's government appears to be caving in . And he said that the deal would have a bad impact on US national security . Speech made to wealthy Jewish donors at Venetian Hotel in Las Vegas . Bush also suggested Obama is losing the war against the Islamic State . Said: 'When you say something you have to mean it - you gotta kill 'em' And he mentioned Vladimir Putin, Hillary Clinton and brother, Jeb Bush .