A 25-year-old Spanish woman who was jailed for over four months in Iran on spying charges and has now returned home after her release last week, said she kept forcing herself throughout her ordeal to think she would go free as she had done nothing wrong.

Ana Baneira, her hair short after prison, told Europa Press news agency on Thursday that not knowing the charges against her for many days while being unable to communicate with other prisoners who spoke no English was probably the hardest part.

"At the start, the uncertainty made it very hard. You fear you'd be accused of spying, which ended up happening," she said in the interview pooling several media, including Reuters.

"You keep hoping that you'll be freed because you've done nothing wrong. The problem is that days go by and they don't release you, so you force yourself into thinking you'll get out."

Baneira, who works for a human rights non-governmental organisation but says she is not an activist, denied taking part in anti-government protests that started after her Sept. 6 arrival in Iran as a backpacker following a tour of Georgia and Armenia.

Demonstrations against Iran's clerical leadership have swept the country since mid-September, when a 22-year-old Iranian-Kurdish woman, Mahsa Amini, died in the custody of the morality police, which had detained her for wearing "inappropriate attire".

Baneira said she was detained in mid-October, a day after visiting an immigration office to request a visa extension that would allow her to stay longer in the country.

At the time of her arrest, she was sitting inside a car with an Iranian friend at a petrol station on their way to the ancient Achaemenid capital of Persepolis.

Another Spanish national, 41-year-old Santiago Sanchez, was also charged with espionage by Iranian authorities and remains in custody since October. He was completing a 6,800-km (4,225 mile) trek on foot from Madrid to Qatar to attend the World Cup there.

Spain's Foreign Minister Jose Manuel Albares called his Iranian counterpart Hossein Amir-Abdollahian on Thursday to press for Sanchez's release, a diplomatic source told Reuters.

Baneira said she was "super happy" to be back in her northwestern hometown of A Coruna, adding that she felt grateful for Madrid's efforts to secure her freedom.