Berlin: An Iranian woman sentenced to death by stoning for adultery was not executed on Wednesday as had been feared, but she remains in danger, an Iranian activist told AFP, citing unnamed sources in Iran.

"Sakineh Mohammadi Ashtiani was not executed today," exiled human rights activist Mina Ahadi from the International Committee Against Stoning told AFP by phone in Germany, where she lives.

"Execution time (for the day) has now passed, so it won't happen today (Wednesday). But the danger remains and it could still happen at any time."

Ahadi and French human rights activists had voiced fears on Tuesday that the mother-of-two, 43, could be executed as early as Wednesday, prompting concern from the European Union and the United States, among others.

"Certain countries, like France, Britain, Italy, the EU, with its representative Catherine Ashton, and the United States reacted very well on Tuesday," Ahadi said.

"Some countries have been in contact with Iranian government representatives. It is clear that all this attention played a role," she added.

"But the execution has been delayed, not cancelled."

She said that according to sources in Iran, Mohammadi Ashtiani's name was on a list of people to be executed in the coming days or weeks drawn up by Iran's Supreme Court.

This was communicated by letter to the prison in Tabriz, northwest Iran, where she is being held, Ahadi added.

In Tehran, foreign ministry spokesman Ramin Mehmanparast accused Western powers of using the case to put "pressure" on Tehran, according to Isna news agency.

A first death sentence, by hanging, for her involvement in the murder of her husband, was commuted to a 10-year jail term by an appeals court in 2007.

But a second, by stoning, was on a charge of adultery levelled over several relationships, notably with the man convicted of her husband's murder, and was upheld by another appeals court the same year.

Mohammadi Ashtiani's son and lawyer were arrested in Iran last month, as were two German nationals, reportedly while interviewing the son. The Germans were granted consular access in late October.

US Secretary of State Hillary Clinton said on Tuesday that Mohammadi Ashtiani's case "has not proceeded with the transparency and due process guaranteed under Iranian law."

"The United States joins the international community in calling for Iran to immediately halt any plans for Ms. Ashtiani's execution and to handle her case with utmost transparency," Clinton said.