TEHERAN - The sixth round of indirect nuclear talks between Teheran and Washington will take place in the Omani capital Muscat on Sunday, said Iran's Foreign Ministry early Tuesday.

Iran and the United States have held five rounds of Oman-mediated indirect talks -- three in Muscat and two in Rome -- since April on Teheran's nuclear program and the lifting of US sanctions. The fifth round was held on May 23 in Rome.

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In late May, the United States presented a proposal to Teheran through Oman for a potential nuclear deal with Iran.

Iranian Foreign Ministry spokesman Esmaeil Baghaei said the US proposal was not the outcome of the previous rounds of negotiations, and Iran would submit its proposal to the United States through Oman.

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He stressed that any proposal disrespecting Iran's national rights, including its right to the peaceful use of nuclear energy and effective sanctions relief, is unacceptable.

Baghaei said Iran's forthcoming proposal would be "reasonable, logically sound, and balanced," urging the United States to consider it seriously. "Accepting this proposal serves the interests of the United States," he added.