Overdose deaths from the opioid painkiller fentanyl — the same drug that killed singer-songwriter Prince in April — have increased sharply in a number of U.S. states, according to a new report.

From 2013 to 2014, eight U.S. states — Massachusetts, Maine, New Hampshire, Ohio, Florida, Kentucky, Maryland and North Carolina — had large increases in overdose deaths tied to synthetic opioids. (The researchers used these deaths as an indicator of deaths from fentanyl, because although they may include deaths from other synthetic opioids, they excluded the high number of deaths from methadone.)

Six of these states specifically reported fentanyl-related deaths, and the combined fentanyl-related deaths in these states increased from 392 deaths in 2013 to 1,400 deaths in 2014, according to the report, from the Centers for Disease Control and Prevention (CDC).

During that same time, the number of drug products that tested positive for fentanyl after being seized by law enforcement officers increased by more than 10 times in the eight states, rising from 293 to 3,340. These products mainly include illegally manufactured fentanyl products that can be mixed with heroin.

The findings suggest that illegally manufactured fentanyl is driving the increase in fentanyl-related deaths, the report said.

"An urgent, collaborative public health and law enforcement response is needed to address the increasing problem of IMF and fentanyl deaths," the researchers said. [Top 10 Leading Causes of Death]

A second CDC report specifically looked at fentanyl-related deaths in Florida and Ohio. It found that, from 2013 to 2014, fentanyl-related deaths more than doubled in Florida (from 185 deaths to 397 deaths) and rose by more than six times in Ohio (from 84 deaths to 526 deaths).

Officers have also recently seized large numbers of counterfeit pills that contain illegally manufactured fentanyl, the report said. This suggests that there could soon be an increase in fentanyl-related deaths in places where people commonly take "diverted prescription pills" (pills that are prescribed to someone else), because people may take the counterfeit pills without knowing it.

The government is working to reduce opioid abuse and opioid overdoses by expanding treatment for opioid addiction, promoting safer prescribing of opioids and increasing the availability of the prescription drug naloxone, which can treat opioid overdose, the report said.

Original article on Live Science.