Monster Energy drinks are under fire for allegedly marketing to children, the Associated Press reported.

San Francisco City Attorney Dennis Herrera and New York Attorney General Eric Schneiderman have joined forces to investigate Monster Beverage Corp., the company they say market highly caffeinated beverages to children, last month, the AP reported.

Herrera has filed a lawsuit against the California-based company claiming that its drinks pose health risks and accusing the company of violating state by intentionally misbranding and marketing its energy drinks to minors. Herrera launched his investigation of Monster Beverage Corp. in 2012.

"We are disappointed that Monster has remained defiant in marketing products to children, he told the Associated Press. "We hope this effort will cause the company to correct its irresponsible marketing practices."

Monster Beverage Corp. filed a lawsuit to try to stop the investigation, but a federal judge threw out the corporation's case.

Monster spokeswoman Tammy Taylor told the AP that the drinks are not marketed to minors and are not highly caffeinated. She said a 16-ounce can of the energy drinks contains less than half the caffeine of a similar-sized coffee cup.

She added that the Monster Energy drink also isn't marketed to pregnant women, or women who are nursing.

This is not the first time the beverage company has been sued.

In October, WebMD reported that a Maryland couple filed a wrongful death lawsuit against Monster alleging that their product is responsible for the death of their14-year-old daughter. They said she collapsed after drinking her second 24-ounce Monster Energy in two days, and died six days later.

The Food and Drug Administration has been investigating reports of deaths linked to Monster Energy drinks but they said there is no solid evidence that the beverages have caused them.

Monster has frequently said its energy drinks are safe and it does not know of any fatalities caused by its products.