Talks between the International Atomic Energy Agency and Iran on Thursday concluded with no measurable outcome, but an Iranian official called them “constructive,” Iranian news outlet Press TV reported.

Iranian Ambassador to the IAEA Ali Asghar Soltanieh told the press that the two parties would reconvene on January 16, 2013, in Tehran.

There was no immediate comment from the IAEA, according to Reuters, and Iranian state TV reported Friday that there was no agreement reached on granting the UN agency access to the Parchin military complex, as the nuclear watchdog has requested on multiple occasions.

Talks with the United States and other nations have been in limbo since June, and IAEA inspectors are still pressing to revisit a military site near Tehran, months after Iran hinted it would give permission for the second visit. Tehran later backtracked and put caveats on the visit.

The West suspects Iran wants to expand its uranium enrichment activities to eventually produce warhead-grade material. Iran says it only seeks reactors for energy generation and cancer treatment, not nuclear weapons.

The talks came as the US stiffened the penalties against Iran over its nuclear program by blacklisting 12 companies and individuals for their work in transferring sensitive technology and uranium enrichment.

The departments of State and Treasury said they’re punishing seven more companies and five more people by freezing any assets they may have in US jurisdictions and barring Americans from doing business with them.

The Treasury said they were targeted because they provide the Iranian government with “unique goods, technology and services” related to the program.

The penalties apply to the procurement arms of the Atomic Energy Organization of Iran and the Iran Centrifuge Technology Company, along with top executives.

The US and its allies accuse Iran of seeking to develop atomic weapons. Iran insists its program is for peaceful purposes only.