The location of manufacture "can be established through a number of different input sources which the Government has access to", he said, adding: "From our perspective, scientific evidence is only one of those sources, and it requires a number of other things to verify that".
British military scientists reportedly have not verified that the nerve agent used to poison ex-spy Sergei Skripal was made in Russian Federation - but said it was "only in the capabilities of a state actor".
Speaking to Sky News on Tuesday, Gary Aitkenhead, chief executive of Porton Down laboratory said the poisonous substance used to carry out the attack was the military-grade nerve agent Novichok but said scientists did not identify where it was manufactured.
"We have not identified the precise source, but we have provided the scientific info to government who have then used a number of other sources to piece together the conclusions".
He also noted that the production of the substance requires "extremely sophisticated methods to create, something only in the capabilities of a state actor".
Russian Federation on Friday expelled 59 more diplomats from 23 countries - including one from Ireland - as relations between Moscow and the West continue to deteriorate to their lowest ebb since the cold war.
Police said they had been exposed to a nerve agent.
He reiterated that the substance could not have come from Porton Down.
She had been given power of attorney over the cash in late February from her father, double agent Sergei Skripal, poisoned by nerve agent Novichok alongside her on March 4 in Salisbury.
The 'secret bank account' was disclosed by Sergei's niece Viktoria Skripal, 45, who aims this week to travel to meet Yulia in hospital in Salisbury.
Struggle hero Winnie Mandela dead at 81
The ANC Women's League (ANCWL) has expressed shock and devastation over the death of Madikizela-Mandela. Ramaphosa said that Nelson Mandela's former wife was a "voice of defiance" against white-minority rule.
Russian President Vladimir Putin says Moscow wants a thorough probe into the poisoning of an ex-Russian spy in Britain and will demand to be part of it.
On Tuesday, the Organization for the Prohibition of Chemical Weapons said it would hold an emergency meeting on the case at the request of Russian Federation, which is demanding Britain hand over its evidence.
"As the Prime Minister has set out in a number of statements to the Commons since 12 March, this includes our knowledge that within the last decade, Russian Federation has investigated ways of delivering nerve agents - probably for assassination - and as part of this programme has produced and stockpiled small quantities of Novichoks". British authorities suspect Skripal was poisoned by a Soviet-made nerve agent.
The diplomatic row has led to more than 100 diplomats being expelled from the UK, Russia, the U.S. and Europe, and the war of words shows no signs of dying down.
A Downing Street spokesman said: "As the Prime Minister has made clear, the United Kingdom would much rather have in Russian Federation a constructive partner ready to play by the rules".
In comments reported by Russian news agencies, Mr Grushko said the attempted murders could have been "arranged by Britain" because "they need a major enemy".
Meanwhile, retired Russian Lieutenant-General Evgeny Buzhinsky warned that relations between Russia and the West could become "worse" than the Cold War and "end up in a very, very bad outcome" following the nerve agent attack.
He said: "It is a cold war".
"We have an interest in a full investigation and want Russian Federation to be allowed to take part in that investigation", he said.