Moscow, Oct 9 (IANS) A Russian investigative committee said Wednesday that authorities have presumably found drugs on board Greenpeace's Arctic Sunrise boat whose crew is under detention for attacking an oil rig in the country's exclusive economic zone last month.

"Drug substances (presumably poppy straw and morphine) have been seized during the search of the vessel. The origin of these substances and their purpose are being determined," Xinhua quoted committee spokesman Vladimir Markin as telling reporters.

Detectives have also found that "some part of the confiscated equipment is of dual purpose and could have been used not only in ecological purposes”, Markin said.

The equipment would be checked by legal experts soon, he added.

The official also said the charges against the 30 activists detained in mid-September were expected to be changed.

"It is obvious to investigators that a number of suspects will be charged with committing other serious crimes," the Interfax news agency quoted him as saying.

Earlier, the committee charged the environmentalists with piracy, alleging they tried to board an oil platform and stage a protest against oil drilling on the Prirazlomnaya platform in the northern Pechora Sea.