Iran's president has warned world leaders that security in the energy-rich Persian Gulf could collapse quickly with a "single blunder" as he accused the US of engaging in "merciless economic terrorism" against his country.
On the same day as President Hassan Rouhani spoke, the US ramped up oil-related sanctions on Iran, imposing penalties on six Chinese companies and their chief executives for continuing to transport Iranian crude.
Mr Rouhani said in his speech to the annual UN general assembly that the US was engaging in "international piracy" against his country by re-imposing economic sanctions after Washington withdrew from the 2015 nuclear deal with world powers.
Iran "will never negotiate with an enemy that seeks to make Iran surrender with the weapon of poverty", Mr Rouhani said in his highly anticipated speech on Wednesday.
"Stop the sanctions so as to open the way for the start of negotiations".
Iranian state television broadcast Rouhani's speech live across the country of 80 million people, many of whom are struggling under the weight of crippling US sanctions that have sent the Iranian economy into freefall and limited Tehran's ability to sell its oil abroad.
US Secretary of State Mike Pompeo and the Treasury Department announced the latest sanctions, which freeze any assets the firms may have in US jurisdictions and bar Americans from doing business with them.
"We're telling China and all nations, know that we will sanction every violation of sanctionable activity," Mr Pompeo said at an event for United Against a Nuclear Iran, a lobby group opposed to the nuclear deal.
Tensions in the region have been increasing as the nuclear deal unravels under pressure from US President Donald Trump.
Mr Rouhani's remarks at the UN came a day after Trump described Iran as "one of the greatest threats" to the planet.
Although Mr Rouhani's manner during the speech was measured, the words he delivered were ominous.
"Our region is on the edge of collapse, as a single blunder can fuel a big fire," he said, adding that it will become secure only when US troops withdraw.
"Security shall not be supplied with American weapons and intervention," he said. "Security cannot be purchased or supplied by foreign governments."
Just before his speech, the remaining signatories to the accord - Russia, China, Britain France, Germany and Iran - stressed they are trying to preserve it.
