Russia has designated the International Transport Workers’ Federation (ITF) as an “undesirable” organization in a step the union said will have significant ramifications for 1.6 million Russian members, the ITF said on Friday.

The label “undesirable” has been applied to dozens of foreign groups since Moscow began using the classification in 2015, and effectively bans an organization outright.

Russia’s Prosecutor General said in a Sept. 5 statement that the ITF posed a “threat” to Russia’s constitutional order.

Russia’s transport ministry declined to comment when contacted on Friday.

The London-headquartered ITF said it refuted all allegations and said it existed “to protect and improve workers’ lives.”

“This designation will have significant ramifications for the 1.65 million Russian transport workers affiliated to the ITF at the time this designation was announced,” it said in a statement on Friday, adding that tens of thousands of Russian seafarers, who sail on ships covered by ITF-approved collective agreements, would be impacted.

“ITF continues to treat Russian seafarers the same as any other seafarer seeking our assistance and support.”

The ITF is an affiliate-led movement of 740 transport workers’ unions across the world, and says it is “the voice of the 20 million transport workers who move the world.”

The Russian branch of Greenpeace said in May it would shut down after authorities declared the environmental group undesirable.