VIENNA (Reuters) -A draft resolution European powers submitted to the U.N. nuclear watchdog's Board of Governors on Monday for a vote this week presses Iran again to explain uranium traces found at undeclared sites and also covers issues such as its barring of inspectors.

The text seen by Reuters follows a resolution passed 18 months ago ordering Tehran to urgently comply with a years-long International Atomic Energy Agency investigation into those traces. The new text calls on Iran to cooperate without delay, including by letting the IAEA take samples if the agency needs to.

It also goes further, addressing problems that have arisen more recently, such as Iran's barring of many of the IAEA's top uranium-enrichment experts on the inspection team. It calls on Iran to reverse that step and implement a March 2023 joint statement that the IAEA saw as a sweeping pledge of cooperation.

"(The Board) Calls on Iran to provide sufficient cooperation with the Agency and take the essential and urgent actions as decided by the Board in its November 2022 resolution, to resolve safeguards issues which remain outstanding despite numerous interactions with the Agency since 2019," the text said.

The 35-nation Board of Governors meets quarterly and is one of the IAEA's two top policy-making bodies. The other meets only once a year.

Since that 2022 resolution the number of sites being investigated over the traces has been narrowed to two from three but Iran still has not explained how the traces got there. The IAEA refers to that as "outstanding safeguards issues".

Britain, France and Germany, known as the E3, are pushing for the resolution despite U.S. concerns the move could lead Iran to respond by escalating its nuclear activities, since Tehran has bristled at such resolutions in the past and taken such steps in response.

The E3 argue that Iran's continued lack of cooperation with the IAEA and its advancing nuclear programme make such a step necessary, diplomats say.

The E3 would not have submitted the text had they not been confident it would pass. Only Russia and China opposed the last resolution against Iran.

Iran is enriching uranium to up to 60% purity, close to the 90% of weapons grade, and has amassed enough material enriched to that level, if enriched further, for three nuclear bombs, according to an IAEA yardstick.

Western powers say there is no credible civilian justification for enriching to that level, and the IAEA says no other country has done so without producing nuclear weapons. Iran says its aims are entirely peaceful.

The text said if Iran failed to cooperate, IAEA Director General Rafael Grossi might draw up a "comprehensive" report, which would raise pressure on Tehran further.

"Continued failure by Iran to provide the necessary, full and unambiguous cooperation with the Agency to resolve all outstanding safeguards issues may necessitate the production, by the Director General, of a comprehensive and updated assessment on the possible presence or use of undeclared nuclear material," it said.

(Reporting by Francois Murphy; Editing by Leslie Adler, Stephen Coates and Lincoln Feast.)

By Francois Murphy