The collapse in Co Kildare of a former acting Russian prime minister at the weekend has been linked to the death of Alexander Litvinenko, the former KGB spy, who died in London from radiation poisoning last week.
Yegor Gaidar (50), considered a chief architect of Russia's early market reforms, collapsed on Saturday at a conference on Irish-Russian relations at the National University of Ireland in Maynooth.
Mr Gaidar was presenting his book Death of the Empire.
Yegor Gaidar
He was brought to hospital in Dublin with a mystery illness. His daughter, Maria, said doctors were unable to provide a diagnosis for symptoms which included loss of consciousness and nose bleeds.
One of Mr Gaidar's associates believes the illness may have been inflicted on him deliberately.
Anatoly Chubais, a close former colleague who heads Russia's state electricity company, said someone may have stood to gain if Mr Gaidar had suffered the same fate as Alexander Litvinenko, the former spy who became an outspoken critic of Russian President Vladimir Putin.
Mr Litvinenko died from radiation poisoning last week after a two-week illness. He left a letter in which he accused Mr Putin of being behind his poisoning. The Kremlin denies any involvement and British detectives are following a line of inquiry that includes a Russian billionaire who also had links with Mr Gaidar.
Mr Chubais drew a parallel between Mr Gaidar's illness, Mr Litvinenko's death and the murder of Anna Politkovskya, an outspoken investigative reporter who was shot dead in Moscow in October.
"Yegor Gaidar on 24 November was in the balance between life and death. Could this be simply some sort of natural illness? According to what the most professional doctors, who have first-hand knowledge of the situation, say - no," he said.
Mr Chubais, the target of an assassination attempt in 2005, said he did not believe Mr Gaidar's illness was the work of intelligence agents working for Mr Putin.
But he said: "For me there is no doubt that the deathly Politkovskaya-Litvinenko-Gaidar chain, which by a miracle was not completed, would have been extremely attractive for the supporters of an unconstitutional, forceful change of power in Russia."
Mr Gaidar - a veteran of Russia's liberal opposition - is currently being treated in a Moscow hospital where doctors at one point feared he could die.
His daughter Maria, who is also a prominent liberal activist, said today that doctors were still trying to diagnose "rather strange symptoms" but she did not want to comment on suggestions he had been poisoned.
Mr Gaidar's stringent programme of market reforms under President Boris Yeltsin helped dismantle Communist economic management but also angered millions whose savings were devalued.
He has made restrained criticism of Russian President Vladimir Putin's economic policies and is now head of the Moscow-based Institute for the Economy in Transition.
A spokesman for Department of Foreign Affairs said Mr Gaidar had been brought to hospital, later discharged and understood to be recovering. "We're not aware of anything untoward," he added.
The Green Party this evening called for gardaí and the Radiological Protection Institute of Ireland (RPII) to investigate.
Justice spokesman Ciarán Cuffe said of radiation levels should be checked at the university and at James Connolly Memorial Hospital in Blanchardstown, where Mr Gaidar was treated.
"No-one wishes to jump to conclusions, but we should err on the side of caution particularly after the discovery of the radioactive material," Mr Cuffe said.
Colm Keane, of the NUI said medics initially suspected Mr Gaidar's fainting was due to diabetes.
"Even though everybody was very conscious of the story coming from London [about Litvinenko] ... we always believed it to be entirely separate from what was going on in London," Mr Keane said.
The Russian news agency Interfax today quoted a spokesman for Mr Gaigar dismissing allegations he had been of poisoned "by radioactive isotopes."
Mr Litvinenko had been killed by the radioactive substance Polonium 210.
Additional reporting Agencies