Iran is accusing US Secretary of State Rex Tillerson of "a brazen interventionist plan" to change the current government that violates international law and the U.N. Charter.Iran's U.N. Ambassador Gholamali Khoshroo said in a letter to Secretary-General Antonio Guterres circulated Tuesday that Tillerson's comments are also "a flagrant violation" of the 1981 Algiers Accords in which the United States pledged "not to intervene, directly or indirectly, politically or militarily, in Iran's internal affairs."

Tillerson said at a June 14 House Foreign Affairs Committee hearing on the State Department budget that US policy is to prevent Iran from developing nuclear weapons "and work towards support of those elements inside of Iran that would lead to a peaceful transition of that government." Khoshroo urged all countries to condemn such "grotesque" statements.

Iran and the United States cut diplomatic ties shortly after Iran's 1979 Islamic revolution and enmity to Washington has long been a rallying point for hardline supporters of Khamenei in Iran. Since U.S. President Donald Trump took office in January, the yawning gap between Tehran and Washington has grown even wider with Trump's latest efforts to isolate Iran in the region, while bolstering cooperation with Saudi Arabia and Gulf countries. Sending a tough message to Tehran shortly after pragmatist Hassan Rouhani was re-elected president, Trump urged Arab leaders to unite to defeat militants, and said Iran had for decades "fueled the fires of sectarian conflict and terrors." Trump's choice of Saudi Arabia, Iran's bitter regional rival, for his first official foreign visit reflects the deep antagonism of his administration towards Iran.Iran, which has been accused of exposing sectarian fault lines in the region, especially in Yemen, Syria and Iraq, tried to soften its rhetoric as Rouhani said there should be greater unity between Shiites and Sunnis and that they had coexisted side by side peacefully for hundreds of years. During the Barack Obama era, Iran enjoyed the opportunity to fill the vacuum in the Middle East after the White House abandoned its traditional allies, like Turkey and Saudi Arabia.

Referring to Iran as "the number one terrorist state," the U.S. president said the Middle Eastern country supplies money and weapons to terrorist groups. The Trump administration hit the ground running, re-imposing sanctions against Iran in its first weeks in office and also instating restrictions against those who are complicit with Tehran.