Ayatollah Khamenei has spoken out against the letter addressed to him by 47 U.S. senators and urged his country’s nuclear negotiators to be wary of U.S. tactics.

Ayatollah Khamenei

Ayatollah Khamenei

Iran’s Supreme Leader said: “This letter reveals the decay of morality in U.S. politics.” He added: “Governments have to abide by their commitments according to international regulations, and a change in government does not warrant violation of those commitments.”

The 47 Republican senators wrote to Ayatollah Khamenei to say an agreement with the current U.S. administration will only be good until the end of Barack Obama’s term.

The letter has been condemned by the White House as well as by Iranian Foreign Minister Mohammad Javad Zarif as lacking any legitimacy in legal terms.

Yesterday, former U.S. secretary of state Hilary Clinton also lent her voice to the criticism of the letter, echoing White House concern that the senators are aligning themselves with Islamic Republic extremists.

Ayatollah Khamenei stressed that every time the negotiations approach resolution, the U.S. begins changing tone and becoming “harsher and more aggressive”, adding that “these are their tactics and tricks”.

Ayatollah Khamenei then proceeded to once again lend his support to the negotiating team headed by Mohammad Javad Zarif but he added: “I remain concerned because the opposing party is deceitful and prone to stabbing others in the back.”

Iran’s nuclear negotiations team has been often criticized by hardliners in the Islamic Republic establishment who are concerned the team is conceding too much in the negotiations.