Evgeny Buzhinsky claimed that diplomatic tensions between Russian and the West are “worse than the cold war” and could end in an armed conflict.
It comes after around 150 Russian diplomats were expelled from countries across the world after Britain accused Russia of using a nerve agent on ex-spy Sergei Skripal and his daughter Yulia in Salisbury.
Retired lieutenant general Mr Buzhinsky told BBC Radio 4's Today programme: "It’s worse than the cold war because if the situation will develop in the way it is now I’m afraid it will end up in a very, very bad outcome.”
Clarifying what he meant by this, he added: “A real war, worse than the cold war is a real war, the last war in the history of mankind.”
He said war could be caused not directly by the Salisbury poisoning but by what has happened since then.
He said: “You see the pressure from the United States, you are saying the pressure will continue – what are you going to achieve?
"If you’re going to achieve regime change it’s useless, actually you are cornering Russia, and to corner Russia is a very dangerous thing.”
Russian Spy Sergei Skripal: Salisbury Nerve Agent Incident
On Monday, a Ukrainian ex-president who was poisoned during a presidential campaign when he faced a Kremlin-backed rival said Europe is "blind" to the dangers posed by Russia.
Viktor Yushchenko, whose meal was laced with toxic chemical dioxin in 2004 as he competed against Viktor Yanukovych, told the BBC in the wake of the poisoning case.
He said: "I would like what we call United Europe to finally realise that the biggest challenge for its citizens is the medieval policy pursued by Russia in the 21st century.”
Russia has repeatedly denied involvement with the poisoning of former double agent Mr Skripal, 66, who was attacked along with his daughter in Salisbury on March 4.
Mr Skripal remains in a critical but stable condition while Ms Skripal, 33, is no longer critical and is said to be showing signs of improvement.
