Greenpeace has accused the Polish authorities using excessive force during a late-night raid on one of its ships after masked officers smashed windows and detained two activists.
A video released by the environmental NGO shows masked men armed with automatic weapons breaking the windows of Greenpeace's Rainbow Warrior with sledgehammers.
Once inside, they point their weapons at activists, yelling "on the ground" and ordering the person filming the incident to stop.
The ship's captain and an activist were detained and are accused of "violating shipping safety regulations," the ministry said in a statement.
The Ministry of Interior said the officers had behaved in a "professional and effective" manner.
The late-night operation came just hours after the Rainbow Warrior anchored at a coal terminal in the port of Gdansk, in the north-east of the country, to prevent a cargo ship from Mozambique from unloading.
The group said the peaceful protest was to draw attention to the country's continued reliance on coal. It estimates that over the past two years Polish imports of coal have doubled to more than 20 million tonnes.
The European Union pledged in the Paris Climate Agreement to cut its carbon emissions by 40% below 1990 levels by 2030.
Cutting coal consumption is key to the bloc achieving that target, according to the Berlin-based Climate Analytics institute.
The NGO calculated that to be compatible with its emission targets, the bloc had to shut down 25% of its 738 operating coal-fired power units by 2020, rising to 72% by 2025 before a complete shutdown in 2030.
The member states most reliant on coal are Poland, Germany, Bulgaria, the Czech Republic and Romania with Germany and Poland jointly responsible for 54% of the bloc's emissions from coal.
"We would like the Polish authorities to act as quickly and decisively in the climate crisis as they do when suppressing peaceful protests," Marek Józefiak, coordinator of the Climate and Energy campaign in Greenpeace Poland, said in a statement.
"The absurdity of the current pro-coal policy of the government is well illustrated by the fact that to reach our country, coal from Mozambique travels nearly 15,000 km. It's more than the diameter of the entire globe.
"Our authorities must finally understand that we do not need more coal. We need a fair energy transformation and the development of renewable energy sources that will ensure Poland's energy independence and new jobs," she added.