Altria (MO) - Get Report and Philip Morris (PM) - Get Report shares shed gains Wednesday after President Trump announced that his administration was considering a ban on flavored e-cigarettes amid an outbreak of a mysterious lung disease.

Speaking in the Oval Office, Trump said that he is holding policy discussions on vaping, especially among underage children, amid an outbreak of a mysterious lung disease that has unofficially killed at least six people. 

Trump said that "very, very strong action" may be needed to protect "innocent children." The administration could go as far as banning flavored e-cigarettes. 

The Food and Drug Administration announced that it was finalizing its guidance to remove e-cigarette flavors other than tobacco from the market because to protect children, U.S. Health Secretary Alex Azar told reporters. 

While the FDA could take several weeks to develop the guidelines, Azar said that the government could take enforcement action if it finds companies have been intentionally targeting children.

The Centers for Disease Control and Prevention is currently investigating more than 450 cases of lung disease that officials think may have been caused by vaping. 

The CDC said that e-cigarettes do have the potential to benefit adult smokers, who aren't pregnant, if they are used as a complete substitute for regular cigarettes and other smoked tobacco products. 

However, on Sept. 6, the agency said that an ongoing investigation into the outbreak of the disease, which is associated with chemical exposure, has revealed cases in 33 different states.

Altria shares turned negative Wednesday, falling 0.54%, while Philip Morris shares pared gains, but remained 0.16% higher following Trump's remarks. 

Altria invested $12.8 billion in the most popular e-cigarette company, Juul, in 2018. Philip Morris announced that it was expanding its e-cigarette business in July.