This article is more than 5 years old

This article is more than 5 years old

Police have arrested eight Spanish men who returned from fighting alongside pro-Russia forces in eastern Ukraine, in what they said was the first operation of its kind in Europe.

Officers detained the suspects in six regions across Spain after they returned from predominantly Russian-speaking eastern Ukraine, the interior ministry said in a statement.

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They had gone to Ukraine last year where they joined pro-Russia groups fighting for independence in the Luhansk and Donetsk regions, the statement added.

The Spaniards belonged to the far left and were inspired by the International Brigades, the multinational volunteer forces that fought against Francisco Franco’s uprising during the Spanish civil war in the 1930s.

They are suspected of being accomplices in killings allegedly carried out by pro-Russia groups, and of possessing arms.

“Their activities can be considered offences that compromise Spain’s peace or independence, as Spaniards who, while taking part in an armed conflict, violate the neutrality Spain must keep in relation to the international community,” the statement said.

The interior ministry said it was the first operation in Europe directed against foreign fighters in Ukraine.

Pro-Russia forces in eastern Ukraine are battling those of the Ukrainian government, which is backed by the west.

The conflict has killed at least 5,800 people since April and it has dragged ties between Russia and the west to their most strained since the cold war.

Over 30,000 foreign fighters are taking part in the conflict, according to the Ukrainian armed forces.

A large number come from Russia and former Soviet states, but many have come from Israel, Serbia, Spain, Italy and Brazil.

“These arrests sadden me,” a leader of Ukraine’s pro-Russian separatist rebels, in Donetsk, Denis Pouchiline, told AFP.

“I think we are going to demand explanations from Spain over this incident. There are many volunteers in our ranks, the greatest number come from Russia, but there are representatives from Spain, Italy, France … it is the first time that they have these types of problems.”

The Spanish combatants had posted online pictures of weapons and messages about their commitment to fighting in Ukraine and had granted several media interviews.

In one web post dated August 2014, a Spanish leftwing group, invoking the example of the International Brigades, called on supporters to go to eastern Ukraine to fight against “the cancer of fascism” that it said was spreading in Ukraine.

In one video posted online one of the men who was detained, a 27-year-old who used the alias “Maki”, trained with an AK-47 assault riffle.

He wore a bracelet with the red, yellow and purple colours of the Republican side in the Spanish civil war, a conflict which pitted leftists against rightwing foes who eventually prevailed.

Another Spaniard who was arrested, a 22-year-old who went by the alias “Zidan”, blamed Washington for the conflict in an interview with Spanish television station La Sexta broadcast in August.

“The United States is trying to provoke the third world war here,” he said.

“I am the only son, my mother, my father, my whole family suffers a great deal but they know that to be happy I have to help people.”

In several online videos he posed without a shirt to show off two portraits of the Soviet leaders Vladimir Lenin and Joseph Stalin which he had tattooed on the right and left side of his torso.