India, July 18 -- Iran Supreme Leader Mojtaba Khamenei on Saturday accused the US of repeatedly breaching its commitments under the memorandum of understanding (MoU) signed between Washington and Tehran, saying the alleged violations showed that the American President's signature was 'utterly worthless and devoid of credibility.'

In a statement read out on state television, Mojtaba also warned the United States of 'unforgettable lessons' if it continued its attacks. He remains out of public view since the war began.

Washington and Tehran have exchanged strikes after a ceasefire agreement fell apart last week, raising fears of a return to all-out war.

This was the first time Mojtaba was addressing the Iranian public since the latest rou...