Dutch officials, testifying Monday at the International Tribunal for the Law of the Sea in Hamburg, Germany, denied Russian accusations of inaction against the protesters, whose ship the Arctic Sunrise was flying Dutch colors Sept. 19 when demonstrators attempted to board a Gazprom oil platform in the Barents Sea.
The Russian coast guard seized the ship and arrested 28 Greenpeace demonstrators and two reporters aboard it.
The Netherlands filed suit at the sea tribunal last month seeking the release of the demonstrators, who initially faced charges of piracy, punishable by up to 17 years in jail. Since then, the lesser charge of hooliganism has been brought, but it was unclear if the piracy charges had been dropped.
Moscow says it was the responsibility of Dutch authorities to detain the Arctic Sunrise, and last week accused them of "inaction" in the run-up to the protest.
But in testimony submitted to the tribunal Monday, the Netherlands claimed the Russians only informed it they intended to arrest the demonstrators one day before the seizure, the Dutch daily De Telegraaf reported.
That made it "impossible for the government of the Kingdom of the Netherlands to take appropriate action," they wrote.
The statement said the Dutch Environment and Transport Inspectorate conducted an investigation of the ship after receiving word from Russia on Sept. 18 it intended to seize the vessel, and "was prepared to act" after determining the activists had violated several maritime safety rules.
But there wasn't time before the arrests were made, the Netherlands said.
However, it added that Greenpeace was exercising its "freedom of expression, freedom of demonstration and freedom of peaceful protest," and continued to demand the activists' release, claiming Russia violated the United Nations Convention on the Law of the Sea.
Russia, meanwhile, argues that the boarding, investigation and impounding of the Arctic Sunrise, and the detention of its crew, were justified because the protesters were within its exclusive economic zone, and has rejected the Hamburg tribunal's jurisdiction in the matter.
Moscow says Greenpeace also allegedly violated domestic Russian laws, but the Netherlands claims that wasn't enough reason to carry out the arrests.
"The detention of the vessel and its crew, irrespective of its conformity with the domestic law of the Russian Federation, is an internationally wrongful act continuing in time," The Hague argued. "The arrest and detention of the persons on board the Arctic Sunrise is not only a breach of the law of the sea, but also of international human rights law."
A decision by the tribunal is expected this month.
Russian authorities began to transfer the "Arctic 30" from Murmansk to St. Petersburg via prison train Monday, Greenpeace said.
"We don't yet know if the relocation of these wrongfully accused people will see an improvement in terms of their detention conditions and basic human rights," Ben Ayliffe, Greenpeace International Arctic campaigner said in a statement. "We are doing everything in our power to ensure that the Arctic 30 are transported in a humane way."