Iran on Monday criticised European Union foreign policy chief Catherine Ashton over an "unsanctioned" meeting she held with rights activists, although newspapers hailed her weekend visit to Tehran.

"Contact with (civil) society is recognised in diplomatic protocol so long as it does not constitute interference in internal affairs and respects customs," foreign ministry spokeswoman Marzieh Afkhan said.

She said that "such incidents do not help relations".

The foreign ministry has issued an "official caution" to the Austrian embassy, which is believed to have organised the "unsanctioned" encounter, she said in a statement carried by ISNA news agency.

Ashton, visiting Iran for the first time since taking up her post in 2009, is tasked with coordinating a diplomatic push by six world powers in talks with Iran on its controversial nuclear drive.

On Sunday, she held talks with top Iranian officials, including President Hassan Rouhani and Foreign Minister Mohammad Javad Zarif.

Ashton on Saturday met with a number of rights activists, including Narges Mohammadi and the mother of Sattar Beheshti, a blogger who died in detention under unclear circumstances in 2012.

"Not surprisingly there was a big focus on human rights. I met with women activists on International Women's Day and talked to them about the situation that women find themselves in," she said.

Iran often draws international condemnation over its human rights record, which it rejects as a case of double standards by the West to put pressure on the Islamic republic.

Mohammadi, 41, has worked with Iran's Nobel Peace laureate Shirin Ebadi at the Defenders of Human Rights Centre, a strong critic of the Iranian regime's treatment of dissidents before it was shut down.

Charged with "acting against national security and propaganda against the establishment", Mohammadi has served lengthy jail terms. She was last freed in 2012.

A hardline figure in Iran's armed forces also condemned the meeting with rights activists.

"Ashton's meeting with some notorious people is proof of a violation of diplomatic rules and a harbinger of future interference" in Iran's internal affairs, said General Masoud Jazayeri, quoted by Fars news agency.

- Press hails 'cooperation era'-

The EU foreign policy chief, however, won praise from the Iranian press for the official side of her visit.

"Iran and Europe enter an era of cooperation," ran the headline in government-run daily Iran alongside a picture of Rouhani receiving Ashton.

Reformist daily Arman said her mission signalled "an extensive revision of the European Union's approach towards Iran," recalling a string of visits by top EU diplomats in recent months.

Another reformist paper, Shargh, argued the visit was a foreign policy success for Rouhani, who came to power in August vowing to mend strained ties with the outside world.

A traditional economic partner for Iran, Europe has been forced out of its markets, including the energy sector, after a deadlock over Tehran's nuclear ambitions led to the imposition of sanctions.

Negotiations on a final accord to allay Western suspicions that Iran's programme masks a military nuclear drive, despite repeated denials in Tehran, are to resume next week in Vienna.

Ashton will chair the so-called P5+1 group of the United States, Britain, France, China and Russia plus Germany in talks with Zarif, following an interim accord struck in November.

In a joint press conference with Zarif on Sunday, she warned that the negotiations on a comprehensive agreement will be difficult.

On the final day of her visit, Ashton travelled to the historic city of Isfahan on Monday.