A prominent Iranian resistance leader is on Monday expected to meet German members of parliament in Berlin, threatening to strain ties with Tehran at a crucial juncture in efforts to curb its nuclear ambitions.

On her first visit to Germany from her base in Paris Mrs Maryam Rajavi, president-elect of the National Council of Resistance of Iran, an umbrella organisation of the People’s Mojahedin Organisation of Iran, will urge Germany to reject the rule of the mullahs and support democratic change.

The PMOI - also known as MKO or MEK - was banned by the US because of attacks on western targets during the 1970s and alleged collaboration with Saddam Hussein’s murderous campaign against the Iraqi Kurds, a charge the group denies. The group is led by Massoud Rajavi, Maryam’ Rajavi’s husband.

Although Mrs Rajavi will not hold talks with government ministers her visit could nevertheless prove awkward for Berlin, which together with Britain, France, Russia, China and the US  has led talks with Iran over its nuclear activities.

Germany has criticised Iran’s nuclear activities and “delaying tactics” but has faced criticism for failing to support tougher sanctions, in part because of a desire to project valuable trade links.

The NCRI said around 150 of 612 Bundestag members from across the political spectrum have signed a petition urging the government to take a tougher line and to support the Iranian resistance.

When he takes office in January US president-elect Barack Obama is expected to pursue a policy of engagement with Tehran, however the PMOI could prove a major sticking point in any future nuclear talks because of its disputed presence on US and EU lists of terrorist organisations.

The PMOI was formed in 1965 to depose the Shah of Iran but after the 1979 revolution the group fell foul of the new clerical regime. Thousands of PMOI were tortured or killed, prompting the group to begin a campaign of violent resistance and forcing many of its members to flee to Europe . 

The PMOI renounced violence in 2001 and committed itself to bringing about a democratic and secular Iran. However, it remains proscribed by the US and EU, in spite of a slew of legal challenges and the NCRI’s extensive lobbying efforts.

Supporters of the PMOI claim European leaders have reused to lift the ban because they are unwilling to antagonise Tehran ahead of future nuclear negotiations. Iran has raised the PMOI’s status during talks with western diplomats and opposes any attempt to reclassify the group.

European ministers are acting in defiance of a ruling last month by the Court of First Instance – Europe’s second highest court - which said a freeze on PMOI’s assets was unlawful and that the “terrorist” label should be removed.

After years of government obfuscation the UK finally removed the PMOI from its own terror list earlier this year after a court ruled its inclusion was “perverse” and “unlawful”.

The cross-party group of German parliamentarians, including members of Chancellor Angela Merkel’s CDU, will call for the lifting of the EU ban and pledge their support for democratic change in Tehran

“If the global community does not want a nuclear Iran and does not want to be confronted with a war, the only solution is democratic change led by the Iranian people and its resistance,” a petition signed by members of parliament and obtained by the Financial Times will say.

Members of the Bundestag are also likely to draw attention to the approximately 4000 PMOI members in Ashraf, Iraq, who could face expulsion to Iran when US troops hands over authority for the camp to Iraqi forces. Supporters fear these people could face torture or death if they made to return to Iran.