No further details have been provided by the outlet so far.
Local officials say that the death toll is expected to rise.
No one immediately took responsibility for the attack.
It is said that the two attackers had detonated bombs in the mosque which led the incident.
Shiite Muslims have remained a constant target of militant attacks across various parts of the country over the past few months.
Other images circulating on social media show bodies lying on the floor outside the mosque.
The attack comes a day after an assault on the Iraqi embassy in Kabul, which was claimed by the Islamic State group (IS), killed two people.
Dozens of local residents, who are mostly Shiites, attacked the police station pelting it with stones and setting it on fire, said Farhad.
It is believed the attack was a suicide bombing.
The attackers, who are both dead, targeted the mosque while around 300 people were inside. The report has yet to be confirmed by local sources in Afghanistan. Herat has previously been the scene of several smaller attacks on Shiites.
It also called "on the Muslim people of Afghanistan, as well as on the religious scholars, to stand united against the barbaric actions of the terrorists".