Kerry's spokesman told reporters in Washington that the two top diplomatic chiefs will hold another day of talks following a meeting at the UN on Tuesday.
Tehran has said it is not receiving enough sanctions relief.
"In these discussions with Foreign Minister Zarif tomorrow, I fully expect that they will continue to talk about the sanctions relief process, and the degree to which banks, foreign and domestic, as well as institutions foreign and domestic are evaluating their options under the JCPOA," State Department John Kirby said Thursday, referring to the Joint Comprehensive Plan of Action as the international nuclear deal is also known.
The two men will address "the degree to which they have before them a sufficient level of understanding to make decisions with respect to sanctions relief," Kirby said at the State Department's daily briefing.
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This week's meetings mark the first face-to-face encounters between Kerry and Zarif since January, when they met in Vienna to formally implement the nuclear deal.
Iranian officials have complained that the United States has not lived up to its side of the nuclear agreement because Western banks and corporations have been reluctant to renew business ties.
Kirby said nothing could be further from the truth.
"We certainly are not trying to become an obstacle in any way of foreign banks and institutions working with Iran through the sanctions relief process and doing legitimate business with Iran," he said.
He added: "We believe we are working hard to try to explain what the obligations are, what the responsibilities are and what the opportunities are for foreign institutions and banks under the JCPOA."
Washington, for its part, has also pointed the finger at Tehran, warning that it retains the right to impose new sanctions over Iran's ballistic missile tests.