Iran has signalled it favours a de-escalation after 10 days of heightened tensions with the
United States during which both sides fired missiles and Tehran accidentally shot down a passenger aircraft.
Security was stepped up in Iran's capital Sunday after a vigil the previous night for those killed in the air disaster turned into an angry protest and
police temporarily arrested the
British ambassador for being there.
US President
Donald Trump warned
Iran against harming demonstrators and against a repeat of a deadly crackdown against rallies in November sparked by a fuel price hike.