BRUSSELS (AFP) ― Six world powers and Iran will hold new talks in New York on Sept. 18, EU and U.S. officials said Thursday, as efforts intensify toward clinching a nuclear deal by a November deadline.

The talks will involve United States, China, Russia, Britain, France and Germany and be led by European Union foreign policy chief Catherine Ashton, her spokesman Michael Mann said.

U.S. officials confirmed the talks would be held at the level of political directors, with the American side led by seasoned negotiator Under Secretary Wendy Sherman.

State Department deputy spokeswoman Marie Harf said she expected the talks will “probably go until the end of the ministerial, the high-level, week” of the United Nations General Assembly.

But she was unsure when foreign ministers, including U.S. Secretary of State John Kerry, would gather around the table.

The talks are being preceded by smaller bilateral meetings in Geneva and Vienna as the sides discuss how to limit Iran’s nuclear enrichment capabilities and number of centrifuges.

The West has long accused Tehran of seeking to develop a nuclear bomb, something the Islamic republic has consistently denied, insisting its nuclear program is purely for civilian energy purposes.

Senior U.S. and Iranian officials met Thursday in Geneva for the start of two days of talks, and Mann revealed that France, Britain and Germany would hold a separate round of talks with Iran at the political directors level on Sept. 11 in Vienna.

Earlier this week, Iranian Foreign Minister Mohammad Javad Zarif said he had had “good discussions” with Ashton in Brussels.

Quoted by the Belga news agency, Zarif said he was “fairly optimistic” after that group and Iran reach a deal by the Nov. 24 deadline.

But Harf urged Iran to cooperate with U.N. watchdog the International Atomic Energy Agency, after its inspectors were refused access to a military base outside Tehran that they have been trying to visit since 2005.

Iran should work “fully and without delay with the IAEA to resolve all outstanding issues, particularly those that give rise to concerns regarding the possible military dimensions of Iran’s nuclear program,” Harf said.