Israel's Prime Minister Benjamin Netanyahu has called the nuclear deal with Iran "an historic mistake" and said it has "made the world a much more dangerous place".
President Obama telephoned Mr Netanyahu this evening to say the US would remain committed to Israel.
Warning: ITV News' Middle East Correspondent Geraint Vincent's report contains flash photography:
When you consider the diplomatic mountain the US and Iran have already scaled, you get a daunting sense of the challenge ahead.
The deal between Iran and world powers looks like a breakthrough, but with six months of wrangling over details ahead, it could still fail.
The nuclear agreement between Western powers and Iran was broadly welcomed by politicians, former world leaders and Middle East experts.