The Internet hacking group published the personal information of congregation members after it was announced Saturday members of the staunchly anti-gay church in Topeka, Kan., would show up at Sandy Hook Elementary School, where 26 children and adults were killed by a gunman who also killed his mother and himself, Mashable.com reported Monday.
The website said Anonymous published private email addresses, phone numbers and home addresses of Westboro congregation members. Anonymous took to Twitter to taunt the church members and posted a video in which it said the congregation of a few dozen people, led by Fred Phelps, was "breeding hatred.'
"We will destroy you. We are coming," Anonymous said.
Westboro Baptist members are known for blaming tragedies on gays and frequently hold protests at military funerals.
Mashable.com said Anonymous had warned the church in February 2011 to end its protest campaign or face the consequences.
"The damage incurred will be irreversible, and neither your institution nor your congregation will ever be able to fully recover," Anonymous wrote at the time.
Meanwhile, two petitions bearing a total of about 83,000 signatures have been sent to the White House seeking to have the church classified as a hate group, Mashable.com said.