Western diplomats cast doubt Thursday on an optimistic assessment by Iran's president, who said his country will likely meet a July target date for a nuclear deal with six world powers.

Iran and six world powers met last week to start drafting a deal, but the talks broke without that work beginning. Neither side gave details of the differences.

President Hassan Rouhani sought to inject optimism into the process on Thursday, telling reporters in Shanghai that a July deal remains "very likely" - although he did not rule out that more time might be needed.

But two Western diplomats told The Associated Press that the two sides are not much closer than they were in February, at the start of the latest round of talks aimed at putting constraints on Tehran's nuclear activities in exchange for sanctions relief. The diplomats spoke only on condition of anonymity because they were not authorized to discuss the talks.

The diplomats said a U.N. report expected Friday will certify that Iran - which denies any interest in nuclear weapons - is honoring a preliminary deal that commits it to limiting certain nuclear activities, including ending enrichment to a level only a technical step from weapons-grade uranium.

Spokeswoman Gill Tudor said the U.N. atomic agency would not comment until the report is published.