A senior State Department official travelling with Kerry said: "There's more work to do, clearly."
Senior officials of the major powers and Iran started a one-day round of talks in Muscat on Tuesday to discuss the outcome of the trilateral meeting between Zarif, Kerry and Ashton.
"There is a capacity to reach a deal by November 24 if there is a political will. At least we can reach a general agreement on major issues," Araqchi told Iranian state TV.
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After leaving Oman, Kerry arrived in Beijing on Tuesday for an Asia-Pacific conference where, officials said, he and U.S. President Barack Obama would confer on next diplomatic steps.
An agreement to curb Iran's nuclear program, which Washington and its allies say may be aimed at building a weapon, would provide a historic foreign policy success for Obama. Iran, which says its nuclear work is for peaceful purposes, would see the removal of punishing economic sanctions.
But, as well as a tight deadline, the complex negotiations face political opposition in the United States, Iran and Israel.
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En route to Beijing, Kerry spoke by phone with Israeli Prime Minister Benjamin Netanyahu, a second senior official said.
On Monday, Netanyahu denounced reported remarks by Iran's Supreme Leader, Ayatollah Ali Khamanei, calling for Israel's destruction, and said he had sent a letter to the foreign ministers of the P5+1 countries - the five U.N. Security Council permanent members plus Germany.
U.S. Republicans, who won control of the Senate in elections last week, are also hawkish on Iran and have threatened it with new sanctions. The Iranians raised the subject of the U.S. elections in Oman, officials said, but did not dwell on it.