Diplomats say complicating factors include order of proposed measures, dealing with advances in Iran’s nuclear processing capability and presidential election in Iran

Tehran was unable to pay due to funds being frozen by US sanctions, money eventually released from Iranian accounts in South Korea; New round of nuke talks set to start Saturday

State Department spokesman insists the move is unrelated to the negotiations, but can't say what 'change in behavior' by Tehran led to the removals

Tehran reacts angrily, saying Washington's 'economic terrorism' prevents it from paying arrears; Central African Republic also stripped of voting rights in upcoming session

White House says progress has been made at Vienna talks and it's a good sign that discussions are continuing

US says fate of nuclear pact up to Iran as talks resume, signals that Terhran shouldn't expect major new concessions

American officials open to lifting penalties tied to terrorism, missile development, human rights; relief would likely anger Israel, Gulf states

In briefing on negotiations for return to nuclear deal, State Department official insists US has been transparent with Israel, including on possible sanctions relief for Iran

But Washington and Tehran have not yet gone into detail during indirect negotiations on the question of which side will take first step

US president has pledged to rejoin 2015 accord if Tehran returns to compliance, but duplicative restrictions imposed by Trump administration complicate the lifting of sanctions