He did not elaborate, but an Iranian Revolutionary Guards commander explicitly said on Wednesday Iran would block any exports of crude for the Gulf in retaliation for hostile USA action.
European powers are putting together an economic package aimed at safeguarding the deal by shielding Iran from some of the impact of USA sanctions resuming.
On Tuesday, the Iranian president appeared to threaten to cut oil shipments from neighboring countries if Washington presses ahead with its goal of forcing all countries to stop buying Iranian oil.
Rouhani said the new US pressure would never succeed.
The arrests were revealed on the day Iranian President Hassan Rouhani arrived in Switzerland on a visit that Tehran said was of "crucial importance" for cooperation between the Islamic Republic and Europe after the United States withdrawal from the Iranian nuclear agreement. Tehran said its foreign minister would meet counterparts from US allies Britain, France and Germany, as well as Russian Federation and China, in Vienna on Friday to discuss ways of maintaining the nuclear deal.
"The formation of this committee means that we will make purchases of goods conditional to purchases of Iran's crude oil and this would limit the impacts of reductions in Iran's oil exports [once the sanctions return]", added Qarehkhani who is the spokesman of the Energy Committee of the Iranian Parliament.
Rohani, accompanied by Foreign Minister Mohammad Javad Zarif, is holding talks with Austrian leaders in Vienna after a stop in Switzerland. Oil remains Iran's lifeblood and supplies roughly 40 percent of the government's revenue. But Britain, China, France, Germany, Russia and the European Union have vowed to keep the pact alive despite Washington's withdrawal. Turkish officials told Foreign Policy Tuesday the government had no reaction yet to the new US demands.More news: Red Alert! Priyanka And Nick Make Couple Entry
The US Navy's 5th Fleet, which patrols the region, has said it has not seen any "unsafe and unprofessional" actions by Iranian naval forces in the Persian Gulf since August 2017.
The US has told India and other countries to cut oil imports from Iran to "zero" by November 4 or face sanctions, making it clear that there would be no waivers to anyone.
He noted the first part of US sanctions will take effect in early August.
The EU's foreign service, the EEAS, was not immediately available for comment on the meeting.
When asked at a news conference in Bern later on Tuesday whether those comments constituted a threat to interfere with the shipping of neighbouring countries, Rouhani said, "Assuming that Iran could become the only oil producer unable to export its oil is a wrong assumption ..."
Rouhani was in Vienna, where his country's nuclear agreement with world powers was drawn up three years ago, to promote the deal's survival after the withdrawal of the United States. On Saturday, Trump wrote on Twitter that he had received assurances from King Salman of Saudi Arabia that the kingdom will increase oil production, "maybe up to 2,000,000 barrels" in response to turmoil in Iran and Venezuela.