"If US savage attacks against the Iraqi people are stopped, we will examine the US request for a fourth round of talks," the unnamed official said, quoted by Fars.
Iran and the United States held three rounds of talks on Iraq last year despite mounting tensions over Tehran's nuclear programme. The talks have been stalled amid controversy over Iran's role in its conflict-torn neighbour.
Tehran, which strongly opposes the US military presence in Iraq, has been repeatedly accused by Washington of arming and training Shiite militia groups in its neighbour.
Iran, whose ties with Washington have been severed since 1980, strongly denies the allegations.
An Iranian delegation travelled to Baghdad in March expecting a new round of talks which never took place. Iran said the United States cancelled the talks at the last minute, but US officials said a date was never set.
"The Iraqi government and the United States have officially invited Iran for the fourth round," the Iranian official said.
"Under the current circumstances and given the US widespread attacks against Iraqi people in different cities, Iran does not feel these negotiations are necessary."
In early April, the United States said it had informed the Iraqi government it was prepared to resume the long-delayed talks with Iran.
US ambassador to Iraq Ryan Crocker and his Iranian counterpart Hassan Kazemi Qomi held face-to-face talks in May and July 2007, in the highest level public contact between the two sides for 27 years.
Officials from the two countries also met at the experts' level last August.
