Velayati, also a senior advisor to Iran's Supreme Leader Ayatollah Seyyed Ali Khamenei on international affairs, made the remarks in an interview with reporters after taking part in Moscow's Valdai Club.
'The only difference between the incumbent president of the US and former presidents is that he openly speaks and does not care about diplomatic politeness in the international arena and therefore his claims are more reflected,' Velayati said.
'No matter polite or impolite the US president is, we have witnessed that the policy of all of them towards Iran has not changed.'
'Obama, Bush, Clinton and now Trump, all, violated their contracts with Iran and others and as we saw they also violated missile agreement with Russia,' Velayati said.
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