EU foreign ministers are set to discuss efforts to keep Iran in line with its nuclear commitments on Monday.
This is coming on the heels of Tehran’s plans last week to partially withdraw from a 2015 deal with major powers.
Iran accepted curbs aimed at preventing it from building a nuclear bomb, in return for relief from crippling economic sanctions.
But Washington pulled out of the pact in 2018 and reimposed punitive measures, hollowing out Tehran’s benefits.
European powers said they would “reject any ultimatums,” after Iranian President Hassan Rouhani last week gave them 60 days to ease the impact of sanctions imposed in the oil and banking sector in particular.
They reiterated their commitment to the deal, while urging Iran to refrain from escalatory steps, in a joint statement by Britain, France and Germany- the three European countries behind the 2015 accord- and EU chief diplomat Federica Mogherini.
The U.S. announced military reinforcements in the Middle East late last week.
Tehran and Washington made clear at the weekend that neither side would back down to defuse the situation.
EU diplomats acknowledge that their bloc has little room for manoeuvre.
Iranian exports to the bloc plummeted in the first two months of 2019 compared to the same period in 2018, according to EU data.
INSTEX, a tool for companies to do barter trade with Iran while avoiding U.S. sanctions, is struggling to get off the ground, diplomats say on condition of anonymity.
Other items on the agenda include Libya, Venezuela and a meeting with ministers from six former Soviet states, marking 10 years of closer ties.