Iran's veneer of stoicism toward the Western sanctions disrupting its economy showed new strains Monday, as the deputy oil minister acknowledged a decline in domestic petroleum production because of dwindling foreign investment, and 4-year-old talks between the Iranians and Poland's biggest natural-gas developer collapsed.

The Iranians also suffered an embarrassment after prematurely announcing that a Russian oil company had committed $1 billion to help revive a dormant oil field in the southwest part of Iran.

Hours later, the Russian company, Tatneft, denied on its website that a deal had been signed.

And there were signals that Saudi Arabia, which Iran had confidently predicted last week would not increase oil production to compensate for any Iranian shortfall, was becoming increasingly irritated.

Together, the developments portrayed Iran, with the world's fourth-largest oil reserves and second-largest natural-gas reserves, as struggling more than it had admitted from the effects of the Western sanctions, despite its official denunciations of them as desperate measures doomed to fail or backfire.

The sanctions, imposed to pressure Iran into ending its suspect nuclear program, were strengthened last month, with the possibility of tougher restrictions on Iran's central bank and oil industry looming from the United States and European Union.

Under a measure likely to be signed into law by President Obama, foreign entities that do business with Iran's central bank, the conduit for Iran's oil revenue, could face severe penalties if they do business in the United States.

Unusually frank

Iran's deputy oil minister, Ahmad Qalebani, appeared to have made an unusual disclosure about the effects of sanctions in an article reported by the official Iranian Students' News Agency, which quoted him as saying Iran's crude-oil production in 2011 had declined from the year before. He said that was "due to lack of investment in oil field development."

Iran produced about 4 million barrels a day of oil in 2010 and is producing about 3.5 million barrels this year.

Qalebani's disclosure comes after warnings by other Iranian officials that the effects of sanctions have become more acute.

The foreign minister, Ali Akbar Salehi, was quoted by the official Islamic Republic News Agency as saying, "We cannot pretend the sanctions are not having an effect." The governor of Iran's central bank, Mahmoud Bahmani, told reporters last week that the country must act as if it were "under siege," Agence France-Presse reported.

The collapsed talks on a deal with Polskie Gornictwo Naftowe i Gazownictwo, a leading developer and distributor of natural gas, involved the Lavan natural-gas field in the Persian Gulf, one of Iran's largest deposits.

Iran's semiofficial Mehr News Agency said the Polish company would be replaced by a consortium of Iranian companies.

It was unclear precisely why the talks failed, but the withdrawal of the Polish company clearly reflected the new pressures on foreign companies not to engage in commitments with Iran.

Even Russia, which has strongly opposed the Western sanctions, appeared to backtrack on a deal after Iranian news agencies said Tatneft had signed a $1 billion agreement to develop the Zagheh field in southern Iran. The company said in a statement it had "not entered into any agreements, contracts" and had "not accepted any other undertakings relating to oil and gas projects in Iran."

Additional pressure aimed at Iran came from Saudi Arabia, Iran's wary neighbor and oil-producing rival. Saudi Arabia's King Abdullah, in remarks clearly aimed at Iran, told a meeting of the Gulf Cooperation Council, a six-member group of Arab oil producers, "No doubt you all know that we are targeted in our safety and security."

Man disputes claim

son is CIA spy

DETROIT — An Iranian American from Michigan who appeared on Iran's state TV is not a CIA spy, as authorities in that country claim and was visiting relatives when he was detained, his father said Monday.

Iran's state TV showed video Sunday of 28-year-old Amir Mirzaei Hekmati and said he was a CIA spy who sought to infiltrate Iran's secret services. The TV said he had received special training and served at U.S. military bases before heading to Iran.

But Ali Hekmati told The Associated Press on Monday that his son was visiting his grandmothers in Tehran when he was detained and never worked for the CIA.

"He is not a spy. It's a whole bunch of lies on my good son," said Ali Hekmati, a microbiology professor at Mott Community College in Flint, about 50 northwest of Detroit. The CIA declined to comment, as did State Department spokeswoman Victoria Nuland.

Iran and the U.S. are locked in a complicated intelligence and technological battle, and the video of Hekmati comes weeks after Iran first displayed a nearly intact American spy drone that it claims it captured and brought down.

U.S. officials say the unmanned aircraft malfunctioned and has demanded Iran return the top-secret aircraft. Iran has refused.

Ali Hekmati said his son was a former Arabic translator in the U.S. Marines who entered Iran about four months ago. At the time, he was working in Qatar as a contractor for a company "that served the Marines," his father said, without providing more specific details.

Amir Hekmati was born in Flagstaff, Ariz., and graduated from Central High School in Flint. From March to August 2010, he worked for BAE Systems, said company spokesman Brian Roehrkasse. He said Hekmati left the company to take a position with the U.S. government as a civilian employee, but he did not have additional details.

Earlier this month, the family of a retired FBI agent who vanished in Iran in March 2007 released a video in which he makes a plea to his kidnappers. The U.S. government has said it has no evidence of who is holding him, and Iran has denied involvement.