TALLINN, Jan 5 (Reuters) - Four men of ethnic Russian origin were acquitted on Monday of plotting 2007 riots in Estonia over the moving of a Soviet-era war memorial, a county court said.

Mainly Russian-speaking protesters went on the rampage for three days in April 2007 after the government moved a World War Two Red Army monument from the centre of Tallinn to a cemetery on the outskirts of the capital city.

"The court decided today that all the persons were not guilty," said Kristina Ots, Harju County Court spokeswoman.

The four men had pleaded not guilty to the charges.

The riots, in which one man was stabbed to death, shocked Estonia and highlighted differences between ethnic Estonians and the large Russian-speaking minority, which makes up about one third of the country's 1.3 million population.

The decision to move the monument also angered Moscow and Estonian-Russian relations have remained tense. (Reporting by David Mardiste, writing by Patrick Lannin; Editing by Sophie Hares)