VIENNA - The top U.S. and Iranian diplomats met for a sixth consecutive day on Sunday to try to resolve obstacles to a nuclear accord, including when Iran would get sanctions relief and what advanced research and development it may pursue.

U.S. Secretary of State John Kerry and Iranian Foreign Minister Mohammad Javad Zarif are trying to meet a Tuesday deadline for a final deal under which Iran would curb its atomic work for more than a decade in exchange for sanctions relief.

Kerry planned to provide an update on the talks at 4:30 p.m. (1030 EDT) outside the 19th century hotel where the talks WEre being held, a senior U.S. official said without providing details.

While they have made some progress on the type of bilateral sanctions relief that Iran may receive, the two sides remain divided on such issues as lifting United Nations sanctions and on research and development using advanced centrifuges.

"Many of the issues related to sanctions have been resolved, and there are four or five issues that remain including the important topic of ensuring both sides' steps correspond to each other and happen at the same time," Iranian Deputy Foreign Minister Abbas Araqchi was quoted as saying by the ISNA agency. (Reuters)