A U.N. agency refused to say if Iran has provided nuclear data requested by Thursday, possibly indicating a setback for investigators, Reuters reports.
Envoys recently said the International Atomic Energy Agency was seeking more detail from Iran on the nation's work with "exploding bridgewire detonators," which can trigger nuclear detonations. Whether Iran offers the information -- one of seven actions it recently pledged to take in cooperation with the agency -- may indicate Tehran's willingness to support a broader IAEA investigation into the nature of its past nuclear activities.
Iran insists its atomic intentions have always been peaceful. Certain observers, though, say Tehran must fully address the watchdog's questions for a multilateral initiative to address suspicions that it wants a nuclear-bomb capability.
On Thursday, delegates from Iran and six other countries began their second day of negotiations on the matter this week, Agence France-Presse reported. The opening day of talks was "intensive and useful," said a spokesman for European Union foreign policy chief Catherine Ashton.
The U.N. nuclear watchdog's remaining questions highlight uncertainties about the degree to which any past Iranian nuclear arms-related studies would affect present-day efforts to rein in the country's weapon-usable atomic efforts, according to Reuters.
Independent analysts David Albright and Bruno Tertrais wrote in the Wall Street Journal that complete information on Tehran's historical nuclear activities is needed "to determine how fast the Iranian regime could construct either a crude nuclear-test device or a deliverable weapon if it chose to renege on an agreement."
One former U.S. official, though, said a comprehensive rundown of Iran's previous nuclear efforts "is not necessary in order to develop a sufficient degree of confidence that those activities are not continuing."
"While full and honest Iranian disclosure of past activities is undoubtedly the best result, such an outcome faces formidable obstacles," according to Robert Einhorn, who last year stepped down as State Department special adviser for nonproliferation and arms control.