Tallinn - Estonian investigators accused Russia on Friday of refusing to cooperate with a probe into cyberattacks in May that forced the closure of government websites and disrupted leading businesses.

The Estonian government believes Kremlin computers were used to carry out a number of the attacks on servers in the Baltic country, which came amid anger in Moscow at the moving of a Soviet-era war memorial in Tallinn.

The prosecutor's office in the Estonian capital said Moscow had brushed off a May 10 request for help in their investigations into the hacking campaign.

"The Russian authorities replied on June 28, 2007, informing the Prosecutor's Office of Estonia that the General Prosecutor's Office of Russia cannot fulfill our request to find the persons who organised the cyberattacks against Estonian websites," State Prosecutor Norman Aasa said in a statement.

Moscow has denied any involvement in the online assault on Estonia, which forced the authorities to temporarily bar access to official state websites.

Some of the attacks also targeted private interests such as banks, hampering their business.

Estonian officials have said the attacks were well organised and, regardless of whether the Kremlin had knowledge of them, were a serious breach of security.

Aasa said Russia's decision not to cooperate was "regrettable", given that other countries understood the need to fight cybercrime and had been assisting Estonia on the issue.

The cyberattacks began after Estonian authorities shifted a the Bronze Soldier statue from a site in the busy centre of Tallinn.

Russia said the move was an affront to Red Army soldiers - the remains of some were buried underneath the monument - who died fighting the Nazis during World War II.

But Estonia argued that the statue, seen by some as a painful reminder of five decades of Soviet occupation, was better-placed in a quiet military cemetery.