But when the Trump administration imposed the sanctions again, the double digit economic growth of recent years was replaced by an economic downturn, as Iran's oil exports have plunged. Amid US sanctions pressure, Ankara's purchases of Iranian oil have declined precipitously to an average of 209,000 tonnes per month between November and April, with imports drying up completely in May.
Before Trump flew to Japan, the United States had announced it was sending 1,500 extra troops to the region, adding to the aircraft carrier group and nuclear-capable bomber planes already dispatched.
U.S. Secretary of State Mike Pompeo said on Sunday that the United States was prepared to engage with Iran without pre-conditions about its nuclear programme but needs to see the country behaving like "a normal nation" first.
Turkey and Iran are now in efforts for an anti-sanctions financial mechanism to be developed for safeguarding trade and economic cooperation between the two countries, the ambassador affirmed. "I think that's very smart of them, and I think that's a possibility to happen".
Last month, Iran partially suspended its commitments under the 2015 deal on its nuclear programs, known as the JCPOA. The US knows there will be "significant costs" should a full-fledged conflict erupt, he said. "It's next to us".
"Just imagine if Iran were to come to California coast [or the] Florida coast", he added.
Sudanese Security Forces Move to Disperse Sit-in in Khartoum
The United States Embassy in Khartoum also joined in the condemnation of the incident calling for the attacks to stop. Eyewitnesses say the protesters have erected barricades and set them ablaze to try to fend off the security forces.
Even Mr Rouhani has been forced to concede the enormity of the crisis his country faces, recently comparing Iran's current economic crisis to the hardships the Iranian people endured during the eight-year war with Iraq in the 1980s.
"My guess is probably what PM Abe is going to suggest is a meeting between [Iranian President Hassan] Rouhani and President Trump on sidelines of the UN General Assembly [in NY this fall]", Vaez said.
But Zarif warned that "there will be consequences" if the USA continues adding more economic sanctions. We have chosen the people and countered terrorism and extremism. We held talks with the USA for several months.
"All options are on the table belongs to the time when the use of force was legal, and that is about 100 years ago", said Zarif. Self defense is allowed.
In an interview with ABC TV, broadcast in Tehran on Monday, Zarif passed remarks on the book "The Art of Agreement", written by Donald Trump, in which the U.S. president describes some trading methods.