Russian investigators claim that hard drugs have been found on board the Greenpeace ship seized during a protest in the Arctic last month.
“During a search of the ship, drugs (apparently poppy straw and morphine) were confiscated,” Russia’s Investigative Committee said.
Poppy straw, or raw opium, can be used to produce morphine or heroin.
Greenpeace said in a statement that any suggestion of illegal drugs being found was a “smear”.
“We can only assume the Russian authorities are referring to the medical supplies that our ships are obliged to carry under maritime law,” it said.
Thirty people are being held on suspicion of “piracy” after activists attempted to scale a Russian oil rig.
The head of Greenpeace International, Kumi Naidoo, has written to Russian President Vladimir Putin, offering himself as a guarantee for the detainees.
There is widespread international concern for the crew of the Arctic Sunrise, who hail from 18 nations.
The Netherlands has demanded the immediate release of the detainees, who are being held in the northern port of Murmansk pending trial, as well as the release of their the Dutch-flagged ship.
In its statement, the Investigative Committee said charges against some of the detainees might change in the light of evidence gathered from the ship.
Apart from the suspected drugs, “dual-purpose” equipment was found on the Arctic Sunrise, it said, adding that this “could be used not only for ecological purposes”.
Investigators would seek to determine who among the detainees was responsible for “deliberately ramming” Russian border guard boats, endangering their lives, it said.
Greenpeace replied: “There is a strict policy against recreational drugs on board Greenpeace ships, and any claim that something other than medical supplies were found should be regarded with great suspicion.
“Before leaving Norway for the Russian Arctic, the ship was searched with a sniffer dog by the Norwegian authorities, as is standard. The laws in Norway are amongst the strictest in the world, and nothing was found because nothing illegal was on the ship.”
“Any claim that illegal drugs were found is a smear, it’s a fabrication, pure and simple,” Greenpeace said.
Greenpeace went on to dismiss the allegation of ramming as a “fantasy”.
In a statement, it released a slow-motion video of its launch and the coast guard boats to show the moment they had touched.
“The Greenpeace boat sails towards the middle of the port side of the security forces boat and then only briefly touches it with the nose, immediately turning away and making a 180° turn to the left,” Greenpeace said.
“The film clearly demonstrates that the official claims are entirely bogus.”
In his letter, Kumi Naidoo wrote: “I would offer myself as a guarantor for the good conduct of the Greenpeace activists, were they to be released on bail.”
In his native South Africa in the 1980s, Kumi Naidoo campaigned against apartheid and was arrested on several occasions.