"As I have previously said, we can not trust in the words of the United States and even in their signature, so negotiations with the United States are useless", Khamenei told a gathering of Iranian diplomats in Tehran.
"(Khamenei) said remarks by the president. that 'if Iran's oil is not exported, no regional country's oil will be exported, ' were important remarks that reflect the policy and the approach of (Iran's) system", Khamenei's official website said.
"You are not in a position to incite the Iranian nation against Iran's security and interests", Rouhani said in reference to those measures.
The White House has also been reaching out to diaspora Iranians, many of whom fled the country following the Iranian Revolution of 1979.
Oil-rich Iran has been seeking a way out of an economic crisis with its currency losing value rapidly as concern has grown about sanctions after the USA backed out of a multilateral agreement with Iran in May. "This would only lead to regret", the official government news agency IRNA quoted Rohani as saying at a July 22 gathering of Iranian diplomats.
Trump has asked countries to cut their oil imports from Iran by November.
Ali Vaez, the director of Iran Project at the International Crisis Group (ICG), says Pompeo's outreach effort is "an exercise in futility".
The Iranians described the USA move as an economic war, said the report.
"We know we are driving Iran to make some hard choices. Threats bring us together", Rohani said, while adding that "we will definitely defeat America".
"We have always guaranteed the security of this strait".
Since the U.S. president pulled Washington out of the nuclear deal, European countries have been scrambling to ensure that Iran gets enough economic benefits to persuade it to stay in the deal.
The group is despised by many Iranians for collaborating with Iraqi leader Saddam Hussein during the bloody 1980-1988 Iran-Iraq War.
Tehran and Washington have been exchanging threats since the latter sought to rip apart the 2015 Iran nuclear deal.