Eritrean website Erimedrek News reported that the women had been detained at Wi'a Military Camp and had begun a hunger strike in protest at the abuse they were experiencing whilst incarcerated.
The site also reported that bruises on the women's bodies suggested that they had injuries consistent with sexual abuse.
The women were admitted to Massawa Hospital on 12 March, where they were guarded by security personnel, but died five days later.
Population: 5.5 million (2.7 million Christians)
Main Religion: Islam/Christianity
Government: One-party state
Open Doors' World Watch List Rank: 10
According to Open Doors, Christians are considered 'agents of the West' in Eritrea and a threat to the state.
Many Christians would rather risk the deadly emigration routes via Sudan or Libya than stay in Eritrea.
According to advocacy group Christian Solidarity Worldwide, thousands of prisoners of conscience are detained for indefinite periods of time and often experience torture.
Since 2002, religious minority communities have been targeted in campaigns of arrest across the country, effectively outlawing all practices not affiliated with Sunni Islam, Catholicism, Evangelical Lutheranism and Orthodox Christianity.
Members of authorised Christian groups also report harassment, detention and persecution.
In June 2016, the UN found "reasonable grounds to believe" that crimes against humanity had been committed by state officials in Eritrea since 1991; including persecution of religious groups and rape by detention officials.
Mervyn Thomas, Chief Executive of Christian Solidarity Worldwide said, "We mourn with the families and friends of these young women, who are the latest known victims of a regime deemed guilty of perpetrating crimes against humanity against its own people.
"It is particularly poignant and harrowing to note they may have died after enduring unspeakable violations that compelled them to adopt a hunger strike, the sole means of protest available to them. Their story is emblematic of many others, whose suffering and deaths fail to register internationally due to the closed nature and pervasive control of the regime.
"It is imperative that this tragedy galvanises efforts by the international community to ensure justice for victims of crimes against humanity, by formalising and initiating processes to identify and hold perpetrators accountable before national, regional or international judicial mechanisms."