Monster Beverage Corp. has filed a lawsuit to stop the San Francisco City Attorney’s office from trying to force the company to limit serving sizes of its energy drinks, as well as its marketing.

The company argues such regulations are a federal matter, The Wall Street Journal reports. Last fall, San Francisco City Attorney Dennis Herrera began an investigation into possible violations of California law involved in Monster’s marketing of energy drinks to children. Herrera last week offered to settle the investigation if the company would take measures including limiting its canned drinks to 16 ounces and 160 milligrams of caffeine, not marketing its drinks to anyone under the age of 18, and strengthening warnings on the products’ labels.

In a statement,  Herrera said, “Monster Energy is claiming an unfettered right to continue marketing its products to children and youth, even in the face of overwhelming evidence that its products pose serious risks to young people’s health and safety. I strongly disagree with Monster’s legal contention, and I intend to litigate this case aggressively to reform their irresponsible marketing and business practices, which I believe clearly violate California’s consumer protection laws.”

In the lawsuit, Monster says its drinks are safe, and are subject to federal oversight by the Food and Drug Administration (FDA). The company says children can order Starbucks coffee, which they say has about half as much caffeine per ounce as Monster energy drinks. The lawsuit also notes that energy drinks Red Bull and Rockstar have similar levels of caffeine as Monster drinks.

In March, Monster agreed to market its drinks as beverages, instead of dietary supplements. The company’s decision came after 18 public health experts asked the FDA to restrict caffeine content in energy drinks. The company’s products will not change, but their label will soon include the amount of caffeine in each can. Monster Energy has been implicated in the deaths of five people.