Senior White House advisor David Plouffe accepted a $100,000 speaking fee from an affiliate of a company doing business with Iran, The Washington Post reported Monday, sparking a political row.
The newspaper said the payment came from a subsidiary of MTN Group, a South Africa-based telecommunications company, which at that time was actively involved in business with a state-owned Iranian telecommunications firm.
The funds covered two speeches Plouffe made in Nigeria in December 2010, about a month before he joined the White House staff, the report said.
US authorities are now scrutinizing MTN Group because of its activities in Iran and Syria, The Post said.
Republicans pounced on the report and said it showed that President Barack Obama's promises to usher in a new ethical era in public life were shallow.
"Today's headlines reveal more ethically questionable conduct by a member of President Obama's inner circle, adding to a growing pattern of behavior," said RNC Chairman Reince Priebus.
"Senior White House advisor David Plouffe profited handsomely by speaking to a company doing business with the radical, anti-American government of Iran."
But White House spokesman Jay Carney said that criticism of Plouffe, who officially joined the presidential staff in 2011, was "misplaced" because his appearance came years before MTN's contacts with Iran came to light.
"This is political criticism after the fact that's clearly designed to try to score some points when this was several years ago, prior to this dynamic we have now with regards to sanctions and companies like this," Carney said.
Carney also said that Plouffe, who helped mastermind Obama's 2008 election campaign before spending several years in the private sector, had held no private meetings with the firm's leadership.
Last week, Obama imposed new economic sanctions on Iran's oil export sector and on a Chinese and an Iraqi bank accused of doing business with Tehran.
Obama said measures would be taken against firms that have dealings with the National Iranian Oil Company, the Naftiran Intertrade Company or the Central Bank of Iran, and those that help Iran buy US dollars or precious metals.
And he accused the Bank of Kunlun in China and the Elaf Islamic Bank in Iraq of arranging transactions worth millions of dollars with Iranian banks already under sanctions because of alleged links to Tehran's nuclear weapons program.
Obama said these two institutions would henceforth be denied access to the US financial system, as would any banks caught dealing with Iran in the future.