(CNN) -- Anger is growing in Mexico over a fire at a government-run day care center that claimed its 46th child this weekend.
Maria Jesus Coronado Padilla mourns for her 2-year-old daughter, who died in the Hermosillo fire.
Parents of the dead children and their supporters have held two noisy rallies in Hermosillo, the city in northwestern Mexico where the fire broke out June 5. They blame the government for laxity in enforcing safety regulations, for conducting a weak investigation and for failing to punish anyone in the 10 days since the fatal blaze.
"It is my fault for trusting them," parent Roberto Zavala said at a rally Saturday in front of the Sonora governor's office. "I am responsible for the death of my child. Mr. Governor: Here is one of those responsible you are looking for. Come get me. I am waiting for you."
The rally was televised nationwide by CNN affiliate TV Azteca.
"If there is no justice from the authorities, there will be vengeance from the people," Zavala shouted to great cheers.
The crowd chanted "renuncia, renuncia" ("resign, resign") toward the office of Sonora Gov. Eduardo Bours Castelo. He did not appear at the rally.
Bours told CNN on Monday that he understands parents' anguish but has not heard any calls for his resignation.
"What we are seeing is natural," he said. "There are destroyed families. It's natural that people express their sadness and, in some cases, anger. And there are those who are using this for political purposes."
The investigation, he said, is "complex and advancing."
Mexican President Felipe Calderon has promised a full investigation.
Officials have said an air-conditioning unit in a government-run warehouse in the same building as the ABC day care center caused the fire. The privately owned day care was leased by the government to provide low-cost service to parents.
Many prominent Mexicans have joined the parents in saying the government is not doing enough to find out what happened and to punish the responsible parties.
"There are 46 children, and nothing is happening," said radio and TV commentator Eduardo J. Ruiz-Healy. "Nobody is responsible. Federal authorities say nothing major happened. There are 46 dead children, and no one will go to jail for it."
Ana Maria Salazar, another TV and radio commentator, also has voiced her anger -- in newspaper columns, on Facebook and on her blogs. Salazar, who lives in Mexico City, grew up in Sonora state and traveled to Hermosillo last week.
"I just returned from Hermosillo, Sonora," she wrote Wednesday on her blog. "Sorrow for the death of the [then] 44 children is now transforming into outrage. The death of these children has impacted Hermosillo, the state of Sonora and Mexico."
She's still angry, she told CNN on Monday.
"My concern is that there are 46 children who died in what appears to be negligence and that nobody's going to be punished," Salazar said.
In addition, she said, the government has not conducted any investigations to see if other day care centers are safe.
"What is unacceptable," Salazar said, "is that nothing has been done to make sure this doesn't happen again."
The United Nations Children's Fund's representative in Mexico, Susana Sottoli, said all day care centers in the nation should be investigated, the state-run Notimex news agency reported Monday.
Last week, Mexican Attorney General Eduardo Medina Mora said officials had found safety irregularities at the ABC day care center in 2005. He declined to detail those irregularities but said authorities are investigating if anything was done about them.
ABC day care officials denied Monday ever being told of safety problems.
Critics point to cozy business relationships between the owners of the ABC day care and government officials. News reports have said one of the co-owners is a cousin of Calderon's wife. Two state government officials whose wives also are ABC co-owners resigned last week.
In all, six officials have resigned or been fired since the blaze.
The well-regarded El Universal newspaper published a column and a story Monday taking the government to task. The article says a Universal investigation revealed that family members and political allies of the governor own at least 13 day care centers in Sonora state. The ABC day care is not one of them.
Bours, who was elected governor in 2003, called the article "malintentioned."
"Some of my relatives had those [day care centers] since before I was governor," he said. "This is a low blow by people who want to link one thing with another."
But Ruiz-Healy calls the day care industry in Mexico "a business run by politicians and politicians' wives."
And he rails at what he sees as arrogance by government officials, whose actions, he said, have led to "a total crisis of credibility."
"There have been a series of events that insult our intelligence," Ruiz-Healy said. "The political class is divorced from reality and from the rest of the country."