Fearing 'real risk of escalation,' Berlin sends envoy after Iran warns that Germany, France, Britain, China, Russia have 2 months to develop plan to block US sanctions

Iranians would rather see tensions with Washington resolved through negotiations, but are prepared to fight if war breaks out

Russian leader meets US Secretary of State in Sochi, insists Iranians have been fulfilling their part of 2015 pact, but warns agreement is 'falling apart' and Europe can't save it

Official from country's atomic agency says move part of 60-day ultimatum laid down by President Rouhani for negotiating new terms

Spokesman for country's atomic agency insists actions ordered by President Rouhani in response to US sanctions do not violate 2015 agreement

Iranian Guards chiefs dismiss US 'psychological war,' say aircraft carrier deployed to region not a threat, but a target; 'If they make a move, we will hit them in the head'

'Things are heating up,' Yuval Steinitz warns as US aircraft carrier sails toward Persian Gulf; Iranian Guards chief dismisses US 'psychological war'

America maintains a vast network of bases, troops and assets throughout the region, to the chagrin of Tehran

Spokesperson says Tehran is eager to see landmark 2015 pact strengthened, as Europe says it won't cave to regime's 'ultimatums'

Iranians have threatened to undermine 2015 pact by restarting uranium enrichment if world powers fail to negotiate new terms. Will Washington's tough posturing pay off?