0120 GMT December 13, 2018
'This may be the worst mistake Trump has made so far,' Cable News Network (CNN) quoted Carter as saying, according to IRNA.
US President Donald Trump announced his decision about the Iran Deal on May 8 and withdrew his country unilaterally from the international agreement.
Many world powers, including Russia, China and the European Union, are against Trump's decision and have declared that they will stay in the deal despite the decision.
'When a president signs an agreement, it should be binding on all his successors, unless the situation changes dramatically and it hasn't changed,' Carter said.
'Unfortunately, I think it signals a message to North Korea that if the United States signs an agreement, it may or may not be honored,' he added.
The veteran American politician also referred to Trump's decision as 'ill-advised'.