Krokodil has made its way into the U.S., two American users told the Daily Mail on Tuesday, despite the DEA denying the flesh-eating heroin alternative is not in the country. Amber and Angie Neitzel, from Joliet, Ill., told the news site that they have used the deadly street drug for more than a year.

The girls agreed to allow the news organization to photograph them to show how the drug has rotted their bodies. [The NSFW pictures can be seen here.]

The Neitzel sisters also provided Facebook pictures that were taken before they started to use the Russian drug to show how its effects on their bodies. So why would they use such a gruesome drug in the first place? According to the girls, they had no idea, at first, that they were taking krokodil -- they thought it was heroin. But once they used krokodil, they never wanted to take heroin again because it was much cheaper and its effects were stronger.

Krokodil, or “crocodile” as it’s also known, is a mixture of desomorphine and toxic liquids such as lighter fluid, paint thinner or gasoline.

Just weeks after first taking the drug, lesions started to appear on the girls' skin. Soon, the Neitzel sisters were infected -- when that happens, users develop scaly, gangrenous sores; hence the nickname “crocodile.”

Angie, 29, was recently rushed to Joliet's Presence Saint Joseph Hospital where she was treated by Dr. Abhin Singla. He told the news site that he knew it was krokodil right away when he saw the scaly sores on Angie’s body. Singla has 16 years of experience and is a leading drug specialist in the medical field.

“I have friends in Russia and I have been following this for some time, I was extremely worried it would come over to the US and now it has,” the doctor said.

He added: “The sores are very different to anything else, they go right down to the bone. It is extremely graphic and worse than anything I've seen before.”

So when he saw Angie for the first time he was sure krokodil was the reason for her lesions. “The moment I saw Angie I knew what she had been taking. It was Krokodil without a shadow of a doubt. All the symptoms matched up 100 per cent.”

Singla said other people have come to him expressing fear that they might have taken the infamous drug.

“I really don't know how it can be stopped, but it has to start with law enforcement,” Singla said about the use of Krokodil. “There have been a number of cases across the country now and something needs to be done.”

Amber, 26, added: "We thought it was just normal heroin, in fact it was actually better because it was cheap and it gave a really intense high, much, much stronger than normal dope."

“But it didn't take long before we both started to get these horrible deep sores on our bodies," she added, "particularly our arms and legs."

She continued: “This is a really bad problem. This drug is real, it rots you away from the inside and attacks your organs. I have been using for 18 months and I know it's done some permanent damage. I will be lucky if I live another ten years from now.”

The DEA has been investigating krokodil use since multiple patients were treated for it at Presence St. Joseph Medical Center in Joliet.