VIENNA - The United States called on Iran on Monday to take "urgent practical steps" to build confidence during nuclear talks with world powers, and the European Union said Tehran must suspend sensitive atomic activities.
Iran and the six powers resumed discussions in mid-April in Istanbul after a gap of more than a year - a chance to ease escalating tension and help to avert the threat of a new Middle East war.
The major powers - the United States, France, Britain, China, Russia and Germany - and Iran are to meet again on May 23 in Baghdad.
"We remain concerned by Iran's persistent failure to comply with its nonproliferation obligations," US envoy Robert Wood told an international nuclear conference in Vienna, attended also by Iran.
"We seek a sustained process that produces concrete results, and call on Iran to take urgent practical steps to build confidence and lead to compliance with all its international obligations," Wood added.