Megachurch pastor John Hagee has come under fire from the influential Anti-Defamation League (ADF) for accusing President Barack Obama of anti-Semitism.

Hagee, whose Cornerstone Church counts 20,000 members, founded Christians United for Israel and is a long-time Christian Zionist.

He told the Zionist Organisation of America that the country's executive branch "is in the hands of one of the most anti-Semitic presidents in the history of the United States of America".

Referring to Obama's statement that the relationship between the US and Israel was "unbreakable", he said: "He knows it's unbreakable because he's been trying to break it for the last five years."

The ADF, which monitors incidents of anti-Semitism, hit back immediately with a statement calling on Hagee to reconsider his remarks, saying they were "offensive and misplaced".

National director Abraham Foxman said: "One can agree to disagree about the president and his administration's record in dealing with Israel, but to apply the label of 'anti-Semitic' is a serious denigration and distortion of the term."

He said that 'anti-Semitic' was a term that should "never be used lightly, or applied to exact a political score or make a political point", adding: "The president continues to be a staunch ally and friend of Israel and friend of the Jewish community. And while we and members of the Jewish community have not always seen eye-to-eye with this administration on certain issues involving the Jewish State, the fact remains that this administration has continued the strong and unwavering alliance with Israel."

Hagee criticised the Obama administration's negotiations with Iran, saying that the president was "anxious to accommodate Iran and its nuclear ambitions".

The headline speaker at the event, US senator and presidential hopeful Ted Cruz, also called on the administration to take a strong line on Iran, saying that Iran should never be allowed to acquire nuclear weapons. "The threats to Israel right now have never been greater, and now is a time when we do not need leaders who simply speak empty words of support for Israel," Cruz said. "We need leaders who will stand and act. Now, more than ever, is a time to strengthen the unshakable alliance and friendship America has with the nation of Israel."