X-rays on ex-Russian spy Alexander Litvinenko, who is ill in hospital in London, have shown up unusual objects that he apparently swallowed.
There is confusion over what has poisoned the ex-spy
A source at University College Hospital told the BBC there were three objects of dense matter in his intestines.
There has been a "major deterioration" in his condition and he is now "very serious" in intensive care.
Anti-terror police have previously said that Mr Litvinenko, 43, was "deliberately" poisoned.
It is not clear whether the objects are the cause of his illness, and the hospital has refused to comment on this aspect.
The X-ray ordered on Tuesday afternoon revealed a round object - possibly a package - about the size of a two pence piece in his left abdomen, and similar sized objects in his colon and small bowel.
One of the objects may have ruptured.
Their position implies that they were ingested but it is not clear what the objects are, how or when they entered his body, or whether they are connected to his illness.
In a statement the hospital said its investigations were continuing and it was not willing to make further comment until it had more information.
The Metropolitan Police said it had no knowledge of the items and the results of toxicology tests were still pending.
His friend Alex Goldfarb said he had spoken to Mr Litvinenko's wife Marina but she knew nothing about any objects.
He said that Mr Litvinenko was on an artificial heart system after a "catastrophic" fall in blood pressure and probably a cardiac arrest.
However, he added: "To my uneducated guess it doesn't mean he is in a fatal condition."
The hospital said Mr Litvinenko was in intensive care in order to receive cardiac monitoring and nutrition and pain relief support.
"He can also be more effectively isolated to protect him against infection following the damage to his immune system," a statement said.
"Our investigations into the cause of his condition continue and we are not willing to make any further statement on this until we have more concrete information."
Mr Litvinenko fled to the UK in 2000, claiming persecution in Russia, and was granted asylum. He is understood to have taken British citizenship this year.
Initial reports said Mr Litvinenko was poisoned with the heavy metal thallium, although medical opinion has not been conclusive and the theory that some form of radioactive material was used has also been put forward.
Friends of Mr Litvinenko claim he was poisoned in London earlier this month because of his criticism of Russian President Vladimir Putin.
Both the Kremlin and Russia's foreign intelligence service, the SVR, have denied any part in poisoning Mr Litvinenko, who is a former security agent with Russia's Federal Security Service (FSB).