A woman in the border city of Laredo, Texas who was angry because she had been denied food stamps killed herself and shot and critically wounded her two children late on Monday, authorities said on Tuesday.

The 38-year-old woman entered the Texas Health and Human Services Commission office in downtown Laredo on Monday afternoon and demanded to speak to a supervisor, said investigator Joe Baeza of the Laredo Police Department.

The woman, whom he declined to identify, pulled out a handgun and started walking through the office, threatening several employees, he said.

She had issues and felt that she had been let down by social services in general, Baeza told Reuters on Tuesday. She was making all sorts of outlandish claims.

She took an office supervisor hostage in a room in the office, he said, and a SWAT team managed to evacuate the other three dozen people in the office and clear the area.

After two hours of negotiations, the woman allowed the male supervisor to go free, but she remained in the office with her two children, a 10-year-old boy and a 12-year-old girl.

About 11:45 last night, she hung up the phone with negotiators, and a little bit later, negotiators heard three shots, Baeza said on Tuesday. What had happened was that she had shot each of her children once and herself once.

The children were airlifted to a hospital in San Antonio in extremely critical condition, he said. The mother was dead at the scene, he said.

Baeza said the woman, who was from Ohio, arrived in Laredo about eight months ago and had lived with her children in several locations around the border city of 236,000.

Stephanie Goodman, a spokeswoman for the Health and Human Services Commission, confirmed that the woman applied for food stamps in July and was denied. Goodman said the woman's application was incomplete and that she was not sure whether the woman qualified for assistance.

We're still trying to track down exactly what happened with the case, she told Reuters. As you can probably imagine, I think she had a lot of other issues she was dealing with as well.

Baeza credited the supervisor with remaining calm and allowing officers to evacuate the other employees and members of the public who were in the building.

He had been with the state agency for 24 years and had been a supervisor since 2000, Goodman said. She said the commission will provide counseling for its workers.

They go into this profession because they really want to help people, so when something like this happens, it's doubly traumatic for them, she said.

She also said the commission will look at what it needs to do to ensure its offices are safe for staff and the public. She said there was an unarmed security guard on duty on Monday at the Laredo office, where Texans can go to apply for food stamps and other programs.

This is the kind of thing you hear of happening in other places, but not in our quiet home town, Baeza said.