His tweet came on the second anniversary of the US withdrawal from the JCPOA.
"On 2nd anniversary of US "ceasing participation" in the #JCPOA, I urged @antonioguterres to hold US accountable for violating its duties & forcing others to do so, too,' he tweeted.
"Lawless bullying jeopardizes @UN credibility & threatens int'l peace & security."
In another tweet on Saturday, Zarif said that humanity will defeat coronavirus and US economic terrorism.
"Today is "Honoring Philanthropists' Day" in our calendar. Charity is an ancient tradition of the Iranian nation," he wrote.
"Over #Ramadan, poor people aided with empathy and millions of masks/disinfectants supplied," he added.
"Humanity defeats #Covid19 and US #EconomicTerrorism. #InThisTogether."
Zarif wrote a letter to the United Nations Secretary-General Antonio Guterres on US deal breakings and sanctions against Iran.
In his letter to the UN Secretary-General, Iran's foreign minister reminded important points on US illegal withdrawal from the JCPOA, unilateral sanctions against Iran, and repeated flagrant violations of the UN Charter, especially the Article 25 which threatens the UN credibility and integrity as well as international peace and security.
MNA/