Iranian authorities confiscated human rights activist Shirin Ebadi's Nobel Peace Prize medal three weeks ago, saying she owes back taxes on her award money. (Jim Buell/Associated Press)

Outrage is growing within the international community after it was revealed Thursday that Iranian authorities had confiscated Nobel Peace laureate Shirin Ebadi's medal.

Ebadi, an Iranian human rights activist, won the Nobel Peace Prize in 2003 for her efforts in promoting democracy. She has long faced harassment from Iranian officials for her activities — including threats against her relatives and a raid on her office last year in which files were seized.

Authorities took the peace prize medal about three weeks ago from a safe-deposit box in Iran, Ebadi said in a phone interview from London.

They also froze her and her husband's bank accounts and demanded about $410,000 US in taxes claimed to be owed on the $1.3 million she was awarded.

Ebadi said, however, that such prizes are exempt from tax under Iranian law.

In Norway, where the peace prize is awarded, the foreign minister said the confiscation of the gold medal was a "shocking first" in the history of the 108-year-old award.

"I would encourage all the governments and other independent voices … in speaking out against this kind of repression," said Jonas Gahr Stoere, Norway's foreign minister.

Geir Lundestad, a top official with the Norwegian Nobel Committee, said the move was "unacceptable." He said the committee was planning to send a letter of protest to Iranian authorities.

Ramin Mehmanparast, a spokesperson for Iran's Foreign Ministry, said Friday that Norway has no right to criticize Iran for enforcing its tax laws.

Norwegian officials are trying to "justify ignorance and avoidance" of paying tax, he said.

Criticized crackdown

Ebadi has criticized the Iranian government's crackdown on demonstrations against President Mahmoud Ahmadinejad and his disputed June 12 re-election. The election was marred by widespread accusations of fraud.

She left the country a day before the vote to attend a conference in Spain and has not returned since. In the days after the election, she urged the international community to reject the outcome and called for a new election monitored by the United Nations.

Ebadi, the first Muslim woman to be awarded the peace prize and the first female judge in Iran, said she would not be intimidated and that her absence from the country since June did not mean she felt exiled.

"Nobody is able to send me to exile from my home country," she said Thursday. "I have received many threatening messages. They said they would detain me if I returned, or that they would make the environment unsafe for me wherever I am."

During the past months, hundreds of pro-reform activists have been arrested, and a mass trial has sentenced dozens to prison terms. Authorities also went after Ebadi's human rights centre in Iran.

Ebadi said she planned to return to Iran when the time is right.

"I will return whenever it is useful for my country," she said. "Right now I am busy with my activities against violations of human rights in Iran and my international jobs."

With files from The Associated Press