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

Officials say discussions include additional Patriot missile batteries, more ships and increased efforts to monitor Tehran

'Under no circumstance will we enter a war,' says Heshmatollah Falahatpisheh, amid soaring tensions

Poll finds Americans oppose preemptive strike on Islamic Republic, but huge majority supports massive retaliation if Iran attacks US forces

'Our steps were very prudent,' Acting Defense Secretary Patrick Shanahan says of US deployment of ships, bombers to region amid intelligence warnings of Iranian attack plans

Foreign minister rejects Trump's offer of talks as long as Washington does not show 'respect,' says there will be 'painful consequences' in the event of escalation

Iran's president says he won't walk away from nuke deal because it would bring more sanctions; Trump says willing to talk, but provocations will be met with 'great force'

President says no current indication of a belligerent act from Iran, but calls them very hostile and the 'No. 1 provocateur of terror in this country'

Dispatched to the Persian Gulf, the USS Abraham Lincoln has yet to enter it, possibly in a bid to calm nerves in the region

Production expected to soon exceed 300-kg stockpile limit under 2015 nuclear accord; Tehran seen abandoning pact after last year's US pullout