Poison plot ahead of EU-Russia summit

The Litvinenko and Politkovskaya incidents appear to be part of a recent upswing in Russian contract killings, with two other men - a Murmansk businessman and a Chechnya officer - also gunned down this weekend.

Mr Litvinenko fell ill on 1 November after being handed documents relating to the case of Ms Politkovskaya in a sushi restaurant in central London, according to press reports.

A medical examination confirmed he ingested thallium, a toxic metal known as the "secret agent's poison" because it is lethal in doses as low as one gram and occurs as an odourless and colourless salt.

Doctors have given Mr Litvinenko a 50-50 chance of survival this week, just as the EU and Russia gear up to discuss future partnership on energy and security at a summit in Helsinki on Friday (24 November).

One main energy goal of the summit is to launch negotiations on a post-2007 bilateral deal that would set "fair play" principles for EU firms trying to enter the Russian oil, gas and nuclear markets.

But a leaked internal NATO memo last week suggesting that Russia may be building up a gas cartel stretching from north Africa to central Asia to use as a political weapon when dealing with Europe.

However, Russia has denied the NATO report saying it will "by no means" put forward any initiative to set up a natural gas cartel on the model of the organization of petroleum exporting countries (OPEC).