International and Irish rage mounted on Thursday as officials in Ireland scrambled to respond to the alleged discovery of the bodies of nearly 800 babies, long dead, stored in a septic tank at a Catholic institution for unwed mothers in western Ireland.

Officials will now investigate whether there are additional mass graves near other homes for unmarried mothers, Agence France-Presse reported Prime Minister Enda Kenny saying Thursday.

Kenny said Irish authorities will “draw together a number of senior officials from across the departments until we see what the scale is, what’s involved here, and whether this is isolated or if there are others around the country that need to be looked at.” He said Dublin must decide what the “best thing to do in the interest of dealing with yet another element of our country’s past.”

Another leading Irish politician, Brendan Howlin, said a criminal investigation may be in the future. “The government is ruling out nothing,” he said, according to the Daily Mail. “The sense of revulsion almost all of the people of Ireland have at the callous disregard for the most innocent of our young people has to be met with openness and with clarity, and that’s what the Government will do.”

The announcements came as international rights groups expressed shock at the grave’s discovery in the western Irish town of Taum. “As disturbing as the ‘Tuam babies’ case is, it must not be viewed in isolation,” Colm O’Gorman, the executive director of Amnesty International Ireland, said Thursday. “The Irish authorities must look into possible allegations of ill-treatment of women and children in other so-called ‘mother and baby homes’ and other institutions run by the state or religious authorities.”

Local leaders also seized upon the issue on Thursday, calling upon the Irish parliament to investigate how it happened. “The history of ‘mother and baby’ homes in Ireland reflects a brutally, unforgiving response by society,” Minister for Children Charlie Flanagan said in the parliament on Thursday.

News of the mass grave of babies’ bodies went viral this week after a local historian named Catherine Corless discovered never-before-released records that pointed to the babies’ remains. She still lives near the institution, known locally as “the Home,” that was operational from 1925 to 1961. According to Irish Central, a local health board in 1944 reported the children living at the Home were  “emaciated,” “pot-bellied, “fragile” and with “flesh hanging loosely on limbs.”

“If you look at the records, babies were dying two a week, but I’m still trying to figure out how they could [put the bodies in a septic tank],” Corless told The Washington Post in a phone interview earlier this week. “Couldn’t they have afforded baby coffins?”

The revelations hinted at Ireland’s dark history of institutions for unwed mothers, who were ostracized as “fallen women.” Worse, the conditions many children experienced at the home weren’t unusual. After Ireland gained its independence in 1916, similar church-run homes sprouted all over the country.

Last year, Prime Minister Kenny apologized for the abhorrent treatment of women who had lived there. “These women were a diverse group: former prostitutes, unwed mothers, orphans, homeless women, convicts and industrial school transfers put in the care of the Catholic Church,” he said. “Nuns ran the facilities… But the inmates were never paid for the work, and all profit went to the church.”

Today, the church has expressed dismay at the mass grave’s discovery. In a statement this week, the Bon Secours sisters who ran the Home said they were “shocked and deeply saddened” and asked for Dublin to “initiate an investigation in an effort to establish the full truth of what happened.”

A statue of the Virgin Mary adorns the site of a mass grave for children who died in the Tuam mother and baby home, in Tuam County Galway Wednesday June 4, 2014. The Catholic Church in Ireland is facing fresh accusations of child neglect after a researcher found records for 796 young children believed to be buried in a mass grave beside a former orphanage for the children of unwed mothers. The researcher, Catherine Corless, says her discovery of child death records at the Catholic nun-run home in Tuam, County Galway, suggests that a former septic tank filled with bones is the final resting place for most, if not all, of the children. County Galway death records showed that the children, mostly babies and toddlers, died often of sickness or disease in the orphanage during the 35 years it operated from 1926 to 1961. (AP Photo/Niall Carson/PA) UNITED KINGDOM OUT NO SALES NO ARCHIVE

A statue of the Virgin Mary adorns the site of a mass grave for children who died in the Tuam home in Ireland. (Niall Carson/AP/PA)

For the Post’s earlier story on the bodies, click here.