Swiss police patrol during the Lake Lucerne Summit from the Buergenstock Resort, on the day of US-Iran talks, in Stansstad, Switzerland, June 21, 2026. [Photo/Agencies]

WASHINGTON - US-Iran talks in Switzerland are ongoing with the US team expecting "to work through the night," CNN reported on Sunday, citing a senior US diplomat involved in the negotiations.

US Vice President JD Vance and the US delegation have been "engaged in constant meetings and negotiations," the diplomat told reporters in Switzerland.

"The Iranians are still here and discussions are ongoing. We anticipate continuing to work through the night," the diplomat was quoted as saying.

During the Sunday talks, the two sides discussed mechanisms to help ensure the Strait of Hormuz remains open, enforce the fragile ceasefire in southern Lebanon and address "all elements of the nuclear deal" in an effort to establish a starting point for technical negotiations, according to the diplomat.