Tehran - Tehran called on the United States Monday not to politicise the case of Iranian-American journalist Roxana Saberi, and to respect the Iranian judiciary's decision and independence.

Saberi was sentenced by an Iranian revolutionary court to eight years in prison for spying for the United States.

Both US President Barack Obama and Secretary of State Hillary Rodham Clinton expressed deep concern over the journalist's fate and their disappointment over the verdict. Obama said Sunday that he was confident Saberi was not involved in espionage against Tehran.

In his Monday press briefing, Iran's Foreign Ministry spokesman Hassan Ghashghavi rejected speculation that Tehran was using Saberi's case as a bargaining chip in future negotiations with the US and called on Washington not to politicise the case.

He said Washington should not make any premature conclusions before studying the case and further rejected any links between Saberi and Iranian diplomats detained by the US in Iraq.

The spokesman reiterated that Saberi had no press accreditation since 2007 and therefore any kind of journalistic activity was illegal.

Reporters in Iran, especially those working for foreign media, require an official accreditation from the Ministry of Islamic Guidance and Culture, otherwise their press activities could be regarded as illegal and even as offending national security.

Ghashghavi, however, said Saberi and her lawyer had the right to appeal the verdict within 20 days, adding that she would have all legal rights as also stressed upon by Iranian President Mahmoud Ahmadinejad.

Ahmadinejad on Sunday called on Tehran's general prosecutor Saaid Mortazavi to personally follow the Saberi case with precision and fairness, in line with all legal norms. He also stressed Saberi's right for legal defence assistance.

Observers consider Ahmadinejad's surprising interference in the Saberi case as an effort by the government to persuade the judiciary to revise the harsh sentence and avoid another international political crisis.

Saberi, 31, a reporter for US National Public Radio, originally faced the less serious accusation of buying alcohol and of working without a valid press card.

She has been in Tehran's Evin prison since January following her arrest on charges of buying a bottle of wine. Both buying and consuming alcohol is forbidden in Islamic Iran.

The judiciary, however, then charged her with espionage, and Tehran's deputy prosecutor Hassan Haddad announced last week that Saberi's case was sent to a revolutionary court which decides in cases involving offences against national security.

Haddad also claimed that Saberi had accepted all charges.

Saberi's Iranian father and Japanese mother are currently in Tehran and plan to stay until they are allowed to take their daughter back home to North Dakota. (dpa)