Dr. Anne Schuchat, principal deputy secretary of the Centers for Disease Control and Prevention, testifies during a House Oversight and Reform Sub-Committee hearing on Capitol Hill, September 24, 2019 in Washington, DC.

WASHINGTON, D.C. — "Hundreds" of new cases of a vaping-related lung disease have been reported to the Centers for Disease Control and Prevention just in the past week, a top agency official told Congress on Tuesday.

The CDC last week said the mysterious lung disease has sickened 530 people so far. Kansas officials confirmed the state's second vaping death on Monday, bringing the total number of fatalities in the U.S. to nine.

Officials are seeing "more and more cases" every day, CDC Principal Deputy Director Dr. Anne Schuchat told the House Oversight and Reform Committee's panel on consumer products at an emergency hearing on the outbreak.

Health officials have linked the illness to vaping, though they are still trying to identify the exact cause. State and federal officials have taken steps in recent weeks to pull flavored e-cigarette pods off store shelves amid an alarming spike in teen use and the recent spate of deaths.

The CDC has more than 100 people working on the investigation, which is complicated by the variety of products and chemicals used in vaping as well as the mix of nicotine and THC, the ingredient in marijuana that produces a high, that's been found in patients who've fallen ill, Schuchat said.

"The identification of the cause or causes for the outbreak may take substantial time and continuing effort," she said.

She recommended that U.S. consumers avoid all vaping products in the meantime.

"At this point I think caution in all products is recommended. It may not even be the THC or the nicotine. It may be the additives or substances that may be common. It may be the material is not labeled appropriately," Schuchat said.

Aside from the illnesses, she flagged e-cigarette market leader Juul's use of salts in its vaping devices as particularly dangerous for teenagers.

"Juul products use nicotine salts, which can lead to much more available nicotine," Schuchat said. She said doctors believe the salts allow nicotine to "cross the blood brain barrier and lead to potentially more effect on the developing brain in adolescents."

executives have said that its nicotine salts give users an experience similar to conventional cigarettes, which the company says helps smokers quit. But the CDC worries about the effects of nicotine salts on the developing brain in young people.

Those effects include difficulty with memory, learning and attention, she said. Nicotine addiction can also prime the body to become addicted to other substances, which is "of particular concern," she said.

Israel announced an emergency ban on flavored e-cigarette sales on Tuesday and said it was considering a full prohibition, according to the Times of Israel. India said it was blocking sales of all e-cigarettes in that country last week, and China is also reportedly tightening its restrictions on the products.