(CNN) After reports of seizures after vaping, the US Food and Drug Administration is alerting the public to a potential new risk and calling for people to come forward with cases the agency might not know about.

The FDA has identified 35 such cases of seizures -- particularly among younger users -- between 2010 and early 2019, it said in a statement Wednesday. The agency has also seen a "slight but noticeable increase in reports of seizures" since June.

The reports were submitted voluntarily, either to the FDA or to poison control centers. The agency stressed that it has not determined a definitive link between vaping and seizures, but there may be additional cases that could help it investigate.

Seizures are known to be a possible side effect of nicotine poisoning, the FDA said.

"We know that nicotine isn't a harmless substance, especially in the developing brains of our youth," FDA Commissioner Dr. Scott Gottlieb and Principal Deputy Commissioner Dr. Amy Abernethy said in the statement. "But we've also been clear that, even for adults, e-cigarettes are not risk free."