British Foreign Minister Phillip Hammond says there was no "breakthrough" yet in the Iran nuclear talks but insisted work was continuing to reach a deal.
"I don't think we're at any kind of breakthrough moment yet and we will do whatever we need to do to keep the momentum," Hammond said on July 2.
Negotiators from Iran and six world powers are working to strike a deal under which Tehran would curb its nuclear program in exchange for sanctions relief.
On July 1, both Iranian and U.S. top diplomats said the talks have been making progress.
"We have made progress and we will make [more] progress," Iranian Foreign Minister Javad Zarif said after a meeting with U.S. Secretary of State John Kerry.
Kerry later told reporters, "We have some very difficult issues, but we believe we are making progress and we are going to continue to work because of that."
On June 30, Iran, Britain, China, France, Germany, Russia, and the United States extended by another week their talks on finding a comprehensive nuclear agreement.
The six powers want limits on Tehran's nuclear programs that could have a military use. Tehran denies it is pursuing atomic weapons.