The US, Britain and France warned Iran Thursday that time was running out for a diplomatic solution to curb its nuclear program.

The statements come days after a third round in talks between Iran and the P5+1 group — the US, Britain, France, Russia, China and Germany — ended with no progress beyond milquetoast statements of “constructive” negotiations.

“Time is wasting,” US Ambassador to the United Nations Susan Rice told a UN Security Council meeting on nuclear sanctions against Iran. “The international community should continue to underscore that Iran must take meaningful steps or face increasing pressure. Yet, we cannot and we will not pursue this path indefinitely. We will not engage in an endless process of negotiations that fail to produce any results.”

Rice added that Iran was nearing bomb-grade enrichment capabilities, in contravention of Security Council and International Atomic Energy Agency resolutions.

“Iran knows the steps it must take to be in full compliance with its international obligations,” she said. “Iran knows the actions required to demonstrate full cooperation with the IAEA. Yet, still, Iran’s approach remains to deny, deceive and distract.”

While sanctions against Tehran have been stepped up in several months, Jerusalem reportedly believes a military strike may be needed to derail the Iranian nuclear drive, which it says poses an existential threat to the Jewish state. It has sought to have the US set out “red lines” which, if crossed would trigger US-led military action, but was rebuffed by the Obama administration.

The United States, Britain and France have all maintained there is still time for sanctions and diplomacy to work.

But the UN Security Council meeting likely signaled growing impatience with Tehran’s obstreperousness.

“The Iranian regime is at a crossroads,” Britain’s ambassador to the UN, Mark Lyall Grant, said, according to AFP. “It can continue to ignore the international community’s concerns over its nuclear program, or it can negotiate a settlement that will help to realize the benefits of a civil nuclear program.”

The meeting was held against the backdrop of reports from the UN’s nuclear watchdog that Iran had been stepping up enrichment activity. On Thursday, Iranian Vice President Fereydoon Abbasi-Davani, who is also the head of the country’s Atomic Energy Organization, told the al-Hayat newspaper that Iran issued false information to protect his country’s nuclear program and to disguise some of the technical advances it has made.

Israel and many Western countries believe Iran is pursuing a nuclear weapon, a charge Iran denies. Tehran has been in fruitless negotiations with the international community for several years over curbing its enrichment activity.

“We are asking Iran to negotiate, but Iran is not negotiating,” France’s UN ambassador Gerard Araud said.