As people around the country mark 4/20 — the unofficial holiday celebrating marijuana — U.S. officials have released new guidance around marijuana for immigrants hoping to earn U.S. citizenship. Officials said Friday that immigrants involved with cannabis in any way — even in states where it has been legalized — could disqualify them from naturalization.

New guidance from the U.S. Citizenship and Immigration Services (USCIS) — which issues green cards and citizenship — says immigrants involved in "marijuana-related activities" could be found to lack good moral character, which is required to gain citizenship. "Activities" include the possession, manufacturing, distribution or dispensing of cannabis, regardless of state laws.

While several states have legalized use of medical and recreational marijuana, the federal government still classifies cannabis as a Schedule I drug — a category that also includes heroin, LSD and ecstasy. According to the United States Drug Enforcement Agency, cannabis has "no currently accepted medical use and a high potential for abuse." The DEA considers it more dangerous than drugs like cocaine, methamphetamine and OxyContin.

We issued policy guidance clarifying that naturalization applicants must comply w/federal controlled substance laws, including those pertaining to marijuana, to establish good moral character during the naturalization application process. Read more here: https://t.co/yqSraeDiBn — USCIS (@USCIS) April 19, 2019

"Marijuana remains illegal under federal law as a Schedule I controlled substance regardless of any actions to decriminalize its possession, use, or sale at the state and local level," USCIS spokesperson Jessica Collins told CBS News Saturday. "Federal law does not recognize the decriminalization of marijuana for any purpose, even in places where state or local law does."

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According to the USCIS, even the use of medical marijuana or jobs associated with the cannabis industry could bar an immigrant from establishing "good moral character" and earning citizenship.

"U.S. Citizenship and Immigration Services is required to adjudicate cases based on federal law," Collins said. "Individuals who commit federal controlled substance violations face potential immigration consequences under the Immigration and Nationality Act (INA), which applies to all foreign nationals regardless of the state or jurisdiction in which they reside."

There is an exception if a violation is a single offense for simple possession of 30 grams or less of marijuana.

Currently, 33 states and the District of Columbia have legalized medical marijuana, and 10 states and the District of Columbia have legalized recreational marijuana for adults.

Sixty-five percent of Americans now think marijuana should be legal — a record high in CBS News polling. Most view marijuana as less harmful than alcohol and believe it is less dangerous than other drugs.