By Alys Davies
Watch: Biden warns Putin not to use tactical nuclear weapons
US President Joe Biden has warned Russia not to use chemical or tactical nuclear weapons in the war in Ukraine.
Speaking during an interview with CBS News, Mr Biden said such action would “change the face of war unlike anything since World War Two”.
He would not say what response the US would make to the use of such weapons.
Russian President Vladimir Putin put the country’s nuclear forces on “special” alert following its invasion of Ukraine in February.
Nuclear weapons have existed for almost 80 years and many countries see them as a deterrent that continues to guarantee their national security.
Russia is estimated to have around 5,977 nuclear warheads, according to the Federation of American Scientists.
It, however, remains unlikely that it intends to use such weapons.
Tactical nuclear weapons are those which can be used at relatively short distances, as opposed to “strategic” nuclear weapons which can be launched over much longer distances and raise the spectre of all-out nuclear war.