Among them were three men hanged in public in Karaj, Alborz Province, on Wednesday.
State media later published photographs depicting their executions.
A 43-year-old mother-of-one, Pari-Dokht Molai-Far, was also hanged in Karaj on Wednesday.
Molai-Far had been imprisoned in the notorious Qarchak Prison for Women in the city of Varamin for three years, before being transferred to Qezelhesar Prison for her execution.
Qarchak Prison, also referred to as ‘Qarchak Death Camp’, was used by the Iranian regime to torture and rape those arrested during the 2009 uprising. The deaths of at least four young protesters while being held at the prison were later condemned across the globe.
Five other death-row prisoners held in the south-eastern city of Kerman, including one woman, were transferred to solitary confinement on Wednesday in preparation for their imminent execution.
On Thursday, the main Iranian opposition began a series of public protests against the soaring executions.
Members of the Iranian diaspora living in Paris assembled on the Esplanade of Human Rights, Trocadero square, Paris, to condemn the human rights violations carried out during the presidency of Hassan Rouhani.
The protesters also called on the international community to protect Iranian opposition members imprisoned at Camp Liberty in Iraq.
Following the July 14 Iran nuclear deal, a number of European officials have travelled to Tehran in the hope of re-establishing economic ties with the mullahs’ regime.
By doing so they are wilfully ignoring the dramatic deterioration in human rights which has seen executions soar since Rouhani was elected in June 2013.
Immediately after the nuclear deal was clinched, the clerical regime embarked on a new wave of executions, including several group hangings.
Some 753 people were executed in 2014, a 10 per cent increase compared to 2013.