Three ex-Soviet states were Friday to agree the first steps towards creating a Eurasian economic union, a project backed by Russian Prime Minister Vladimir Putin to bind closer the former USSR.

Russian President Dmitry Medvedev and his Kazakhstan and Belarus counterparts Nursultan Nazarbayev and Alexander Lukashenko were to sign a declaration on further economic integration at a summit in Moscow, the Kremlin said in a statement.

"The declaration will set out the ultimate aim (of economic integration) as the creation of a Eurasian economic union," it said.

Putin first evoked the idea of creating a Eurasian Union in a newspaper article published shortly after the announcement that he would seek to return to the Kremlin as president in 2012 polls.

The three countries already have a customs union but the creation of the Eurasian Union -- which would have its own executive body and oversee a single economic space -- would mark a huge step further.

The single economic space is due to come into force in 2012 alongside a Eurasian Economic Commission, a body that would apparently be run on lines similar to its Brussels-based EU equivalent.

"The commission -- the first such in post-Soviet history -- will be neutral in relation the countries involved and will gradually take on national powers," the Kremlin added.

The Kremlin did not give a date for the creation of the Eurasian Union itself but the Vedomosti daily quoted sources as saying that 2015 would be given as the target date.

The initial members would be Belarus, Kazakhstan and Russia but any ex-Soviet state would be welcome to join, it added.

Putin in his article said the union would build on the experience of the European Union and would be a "historic breakthrough" for ex-Soviet states.

The prime minister, an ex-KGB officer who once described the Soviet collapse as the greatest geo-political tragedy of the 20th century, denied he simply wanted to recreate the USSR under another guise.

It remains unclear what impact the project could have on Russia's entry to the World Trade Organisation, which is finally expected to be agreed by the end of this year after 18 years of negotiations.