The artist was headlining at the "Beach, Please!" festival in the eastern Romanian village of Costinesti on the Black Sea coast.

What do we know about the charges against Wiz Khalifa?

Prosecutors said that Khalifa was found to have had cannabis in his possession.

"During a performance at a music festival held in Costinesti, the accused was found to have possessed more than 18 grams of cannabis and to have consumed (on stage) another quantity in the form of a handmade cigarette," Romanian anti-organised crime prosecutors (DIICOT) said in a statement.

Prosecutors said that the investigations into the artist are ongoing.

Videos posted on social media show Khalifa being escorted out of the festival by police.

In a post on X, formerly Twitter, Khalifa said that officers had been "respectful" during his arrest and that he was released from custody.

"Last nights show was amazing. I didn't mean any disrespect to the country of Romania by lighting up on stage," Khalifa said.

"They were very respectful and let me go. I'll be back soon. But without a big ass joint next time," he said."

Wiz Khalifa arrested amid anti-drug campaign

In the US, the recreational consumption of cannabis is legal in 24 states and in an additional 14 states it is allowed for medical use.

Khalifa often raps about smoking marijuana in his lyrics and has endorsed legal cannabis brands.

In Romania, cannabis is classified as a "risk drug" and a possession conviction can carry up to 10 years in prison.

Romanian media reported that "Beach Please!" was the site of an anti-drug campaign launched by YouTuber Andrei Selaru, who is a co-founder of the festival, in coordination with the Romanian Interior Ministry.

Romania's Antena 3 CNN broadcaster said that the festival was to have an estimated participation of around 200,000.

Khalifa is not the first US rapper to be detained for cannabis possession while touring in Europe. In May, Nicki Minaj was detained at Amsterdam Schiphol airport for allegedly "exporting soft drugs."