Border officials in Arizona on Sunday discovered a new version of "rainbow" fentanyl pills that had never before been encountered. 

U.S. Customs and Border Protection officers made the new discovery at the Nogales Port of Entry in southern Arizona. 

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fentanyl pills seized by Customs and Border Protection

A new type of rainbow-colored fentanyl pills.  (CBP)

Port Director Michael W. Humphries said around 413,000 fentanyl pills were seized. Of those, around 44,000 of the pills had the distinct rainbow color combination, he said. 

CBP officers also seized 7.4 pounds of fentanyl powder and 14.4 pounds of heroin. No further details on the seizure were released. 

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The U.S. Drug Enforcement Administration issued an advisory in August, warning the public of an "alarming emerging trend" of colorful fentanyl – dubbed "rainbow fentanyl in the media – available across the United States. 

The DEA has warned that the colorful pills are designed to attract children, sparking fears that the drug will put kids in danger on Halloween – though some experts have disagreed with that conjecture. 

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"Rainbow fentanyl—fentanyl pills and powder that come in a variety of bright colors, shapes, and sizes—is a deliberate effort by drug traffickers to drive addiction amongst kids and young adults," DEA Administrator Anne Milgram said in a statement.  "The men and women of the DEA are relentlessly working to stop the trafficking of rainbow fentanyl and defeat the Mexican drug cartels that are responsible for the vast majority of the fentanyl that is being trafficked in the United States."

Fox News’ Michael Lee contributed to this report.