An explosion has killed at least eight people and injured 18 others during Friday prayers inside a mosque in the Syrian city of Homs, the health ministry has said.

Pictures from Syria's state-run news agency, Sana, show the inside of the Imam Ali ibn Abi Talib Mosque with black, scorched walls, smashed windows, and blood on the carpet.

Officials believe that an explosive was detonated inside the building, Sana reports, citing a security source. While authorities are still searching for the perpetrators, jihadist group Saraya Ansar al-Sunnah has claimed responsibility.

The mosque is in the Wadi al-Dhahab neighborhood, where most people are part of the Alawite ethnoreligious group.

Syria's Foreign Ministry condemned the terrorist crime, writing in a statement that the cowardly act is a blatant assault on human and moral values designed to undermine the security and stability of the country.

Saraya Ansar al-Sunnah, a Sunni extremist group, has claimed it carried out the attack in collaboration with another unidentified group using explosives planted at the site.

The group's vague origins and affiliations, which came to prominence in June when it claimed responsibility for a deadly church bombing in Damascus, raise questions about its true links and authenticity.

Some observers speculate it may be a front for the Islamic State group (IS) given the similarities in their messaging and types of targets.

The latest claim follows a lull in Saraya Ansar al-Sunnah's claimed attacks, which have largely consisted of targeted killings of minorities and former government affiliates.

The blast comes a year after Syrian rebel forces overthrew Bashar al-Assad, whose Alawite sect is one of the country’s largest religious minorities. Since then, there have been several waves of sectarian violence, complicating the situation for the Alawite community.

In March, security forces were implicated in the deaths of dozens of Alawites, according to war monitoring group Syrian Observatory for Human Rights (SOHR).