PRAGUE (Reuters) - Czech police have detained five people on suspicion of terrorism-related offences connected to fighting on the side of pro-Russia separatist forces in eastern Ukraine, prosecutors said on Wednesday.
The Prague High Public Prosecutor's Office said the five people detained had not yet been charged but were taken into custody on suspicion of terrorist acts, financing terrorism and supporting terrorism.
"These criminal acts relate to involvement of Czech citizens in the fighting in eastern Ukraine on the side of the so-called (rebel) Donetsk People's Republic," it said in a statement.
The arrests came amid high tension between Prague and Moscow following Czech allegations that Russian military intelligence was behind 2014 explosions at an arms and ammunition depot in which two people were killed.
The central European country on Saturday expelled 18 Russian Embassy staff, whom it identified as intelligence officers, over the matter. Moscow denied any of its agents were involved, branded the Czech stance a provocation and expelled 20 Czech diplomats and other staff in retaliation.
Czech police said on Twitter there was no connection between the two investigations. A police spokesman said more details would be released later on Wednesday.
Public Czech Radio reported, citing information from the investigation, that the arrests targeted a paramilitary group and that one of its members had fought for the rebel side in Ukraine and upon his return had raised money to send others.
Several other Czechs have faced trial in the past connected to the fighting between Russian-backed separatist insurgents and the Ukrainian army in which the Kyiv government says around 14,000 people have been killed since 2014.
The Czech-Russian row over the 2014 arms depot blasts has worsened tensions between Russia and the West over what Ukraine's allies have called a "provocative" build-up of Russian military forces on the Ukrainian border and in Crimea, the peninsula Moscow annexed from Kyiv seven years ago.
Ukrainian Foreign Minister Dmytro Kuleba said on Tuesday Russia would soon have more than 120,000 troops on Ukraine's frontier, and called for new Western economic sanctions to deter Moscow from "further escalation".
The dispute is the biggest between Prague and Moscow since the end of Soviet domination of Eastern Europe in 1989.
(Reporting by Jason Hovet; Editing by Mark Heinrich)