Nine American citizens have been arrested and charged after allegedly trying to smuggle drugs from Los Angeles to London, British officials said.

Additionally, more than $6.7 million worth of cannabis (or £5.5 million) was seized, according to the National Crime Agency in the U.K.

The passengers were flying from Los Angeles to London’s Heathrow Airport when they were taken into custody last week.

Each were found to have between 30 and 50 kilos of marijuana checked in their baggage, officials said.

The first passenger arrived on Jan. 10 and officers with Border Force seized around 30 kilos from suitcases.

A second seizure was made on Jan. 13, followed by two more on Jan. 14, four on Jan. 15 and an additional one on Jan. 16, officials detailed.

“In total more than 340 kilos of herbal cannabis with an estimated street value of more than £5.5 million has now been seized,” NCA officials detailed in a news release.

All nine suspects, five women and four men, were charged with attempting to import class B drugs and remain in custody pending court appearances.

No further details about the smugglings have been released.

“We are working to understand how these seizures are connected, however to get this many off the same route in such a short period of time is clearly very unusual,” NCA senior investigating officer Darren Barr said. “Drugs couriers face stiff sentences so I’d urge anyone considering getting involved in such ventures to think very carefully about the consequences.”