One of the papers, Hammihan, was banned in 2000 by the hard-line judiciary after it called for improved ties with the United States, touted by the government as Iran's biggest enemy.
On Sunday, the paper was back on the newsstands, and its top story -- with the headline "Iran-US talks in Baghdad" -- was on an agreement announced by the two countries over the weekend to hold ambassador-level talks on the situation in war-torn neighboring Iraq.
The other paper, Shargh, which had been banned last year after it poked fun at Ahmadinejad in a cartoon, resumed publishing on Monday.
The decision to allow the papers to re-open appeared to reflect a feeling among Iran's unelected clerical leadership that it must allow a margin of expression for the opposition amid mounting discontent with Ahmadinejad at home.
The clerical leadership controls the judiciary and backed Ahmadinejad in his 2005 election victory that brought him to power. But conservatives who once supported the president have joined his critics, saying he has ignored mounting economic woes and has needlessly provoked the West against Iran in disputes over its nuclear program.
"Given the ... threats against Iran, the ruling establishment has decided that opposing voices need to be heard, although Ahmadinejad's government may not like it," Mahdi Rahmanian, editor of Shargh, which resumed publishing Monday, told The Associated Press.
The move restores some degree of opposition voice at a time when Ahmadinejad's government has stepped up a crackdown on some critics, particularly pro-democracy advocates, fearing they may be part of U.S. moves to foment regime change.
Last week, authorities arrested a prominent Iranian-American academic, Haleh Esfandiari, and a hardline newspaper accused her of spying for the United States and Israel and trying to start a revolution inside Iran. Her family has denied the accusations.
The Iranian leadership is under multiple pressures -- trying to avert further U.N. sanctions over its nuclear program even as the United States has taken a more aggressive stance against what it calls Iranian meddling in Iraq. Washington accuses Tehran of backing militants there, a charge Iran denies.
At the same time, Ahmadinejad's political rivals have been gaining ground. Local elections in December brought an embarassing defeat for his hard-line supporters as reformists and conservatives opposed to the president won dominance in many city councils across the country.
Last week, the Tehran city council re-elected an Ahmadinejad rival, moderate conservative Mohammad Bagher Qalibaf, as mayor of the capital, strengthening his position to run against Ahmadinejhad for the presidency.
Conservatives and reformists have complained about Iran's worsening economy, with housing prices doubling and prices for some basic goods such as vegetables tripling in the past six months. The government is planning to increase the price of gas and also impose rationing, a decision that has caused great concern for the public.
The clerical leadership may be hoping that the return of some reformist newspapers will provide a safety valve for the discontent.
The judiciary closed down more than 100 reformist papers during the last years of the rule of Ahmadinejad's predecessor, pro-reform President Mohammad Khatami -- part of the struggle for power between reformists and hard-liners.
"We remain committed to our reformist goals. There is only one hope that directs us in continuing this path: Trying to offer a clearer support for freedoms," said one of Hammihan's editors, Mohammad Ghouchani.
Many of the writers in the two newspapers are well-known reformists who have spent years in jail for opposing strict interpretations of Islamic rule by hard-line clerics and supporting democratic reforms and freedoms. Hammihan's chief manager is Gholamhossein Karbaschi, a former Tehran mayor and Khatami ally who was jailed in 1999 on graft charges that were seen to be politically motivated.
Khatami congratulated Hammihan on its rebirth, calling it a "dignified" newspaper.
"Thank God that as far as possible we promoted free flow of information and respected journalists ... although the press paid a high price for it," he said in a message to Hammihan.
By: Two pro-reform newspapers that had been banned -- one of them for the past seven years -- resumed publishing this week in a sign of the decreasing popularity of hard-line President Mahmoud Ahmadinejad.