NATO launched Wednesday a new cyber-defence training centre in Tallinn to defend against attacks over the Internet, a year after Estonia fell victim to a "cyber-war" blamed on Russian hackers.

At NATO headquarters in Brussels, seven member nations -- Estonia, Germany, Italy, Latvia, Lithuania, Slovakia and Spain -- signed documents formally establishing the Cyber Defence Centre of Excellence in the Estonian capital.

"The need for a cyber-defence centre to be opened today is compelling," said General James Mattis, who heads NATO's transformation efforts. "It will help NATO defy and successfully counter the threats in this area."

The centre, due to open officially in 2009 but which has already been working informally, will conduct research and training on cyber warfare and have a staff of 30, half of them IT experts from the participating countries.

The choice of Estonia is no accident: besides having first-hand experience of a cyber-war, the country is home to a flourishing hi-tech industry which has earned it the nickname "E-stonia".

In late April and early May last year, a flood of attacks forced the temporary closure of Estonian government websites and disrupted leading businesses in what is one of the world's most wired economies.

While Estonia has prosecuted several young ethnic-Russian hackers based in the Baltic state, most of the cyber-soldiers were believed to be operating from Russia itself, out of reach of Estonian justice.

The attacks came after Estonian authorities decided to shift a Soviet-era monument from central Tallinn to a military cemetery. The move was marked by riots in the capital on April 26-28.

Afterward, relations between Moscow and Tallinn plunged to their worst since Estonia regained independence.

Tallinn has said that even Kremlin computers were used to carry out some of the attacks. Moscow has denied any involvement.