An Iranian Christian sentenced to 10 years in prison has been released after three months.

Mostafa Bordbar, 27, was released Nov. 3 from Tehran's Evin Prison after overturning charges of participating in an "anti-security organisation and "gathering with intent to commit crimes against Iranian national security".

Bordbar was arrested in December last year during Christmas celebrations with friends and sentenced in July. He was detained for a total of 11 months.

The Oct. 30 appeals court hearing cleared him of all charges.

Iran has come under increasing pressure from the international community to improve its human rights record, including its number of political prisoners or other prisoners of conscience, such as the more than 40 Christians behind bars.

In September, two Christians were released, a decision welcomed internationally. Mitra Rahmati and Maryam Jalili were nearing the end of their sentences, and were released just ahead of new President Hassan Rouhani's first address to the U.N. General Assembly in New York.

The U.S. ambassador to the U.N., Samantha Power, took to Twitter on Sept. 18 to hail the release of prisoners from Iran's jails. "But it's far from enough," she wrote. "Those missing or unjustly detained, including Amir Hekmati, Saeed Abedini, and Bob Levinson, must be returned home."

Hekmati is awaiting retrial in Iran on espionage charges. Levinson was kidnapped in Iran in 2007 and is believed to remain in government custody. Meanwhile, Abedini, an Iranian-born US citizen and pastor serving eight years in prison for his missionary work, has written to Rouhani asking for justice and freedom.

At least 300 Christians have been arrested in the past three years in Iran, with the most common charges being actions against public security and propaganda against the regime. Many of these Christians were arrested while taking part in "house churches", small meetings of Christians who gather to worship and pray together.

"In bringing about these charges against Christians, both the government and the judiciary have made an error of law and fact because Christian gatherings either at homes or churches are mainly formed for Christians to worship together and to read and study the Bible, not to change the regime, and they do not have a goal of any political activity.

"So these are wrong judgments," human rights lawyer Attieh Fard told the United Nations Human Rights Council last month.

Fard urged Rouhani to make good on his promises to the U.N. in New York by releasing the 42 Christians known to be in jail and the 45 awaiting trial.

Bordbar's victory in court comes one week after another four Iranian Christians lost their own appeals, having been convicted of similar charges.