Mousavi made the remarks during his weekly press conference which was held with the participation of reporters as the country is easing restrictions due to the spread of COVID-19.
Health protocols were however fully observed during the press conference.
The NAM meeting is due in Baku, Azerbaijan later today (on Monday) with the participation of 46 heads of states, Mousavi said, noting that President Rouhani will take part in the meeting via video conference as the coronavirus disease still continues across the world.
The Iranian spokesman said that the NAM meeting will focus on ways to respond to the pandemic.
Noting that despite the problems facing different countries and the entire world, diplomacy cannot be stopped, Mousavi said that Iranian Foreign Minister Mohammad Javad Zarif has had 22 telephone conversations with different international and regional officials over the past days.
He also referred to a visit to Afghanistan by Iranian Foreign Ministry's special assistant for Afghanistan affairs Mohammad Ebrahim Taherian, expressing hope that such efforts would yield fruit.
Mousavi touched upon the anniversary of the US unilateral exit from Iran nuclear deal, saying the US has a historic record in failing to honor its international commitments.
US unilateral approach to Iran deal showed that Washington does not believe in the rule of law and international law and is the biggest violator of international regulations, he said.
The spokesman also said that while the world is grappling with the rapid spread of coronavirus disease, Washington threats to cut its financial support for the World Health Organization (WHO). He urged all world countries to provide support for the organization.
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