Russia is "playing with fire" in attempting to intimidate with threats of nuclear force, and the US is determined to prevent it gaining a military advantage through violations of international nuclear regulations, deputy US defence secretary Robert Work has said.
Speaking to the Armed Service Committee in the US House of Representatives, Work said that Russia's attempt to bully its neighbours with aggressive nuclear rhetoric had failed, and had only succeeded in bringing Nato allies closer together.
Addressing lawmakers, he called for additional funds to be approved for renewing the US's nuclear programme, with spending to rise from 4% of the defence budget to 7%.
He described Russia's strategy as "escalate to de-escalate", reports Reuters.
"Anyone who thinks they can control escalation through the use of nuclear weapons is literally playing with fire," Work said.
"Escalation is escalation, and nuclear use would be the ultimate escalation."
He added that Russia continues to violate the Intermediate Nuclear Forces (INF) treaty, which bans ballistic and cruise missiles with a range of 500m to 5,500m.
Work said the Pentagon was working on options to present to US President Barack Obama as a response to treaty violations, and that the US would not let Russia "gain significant military advantage through INF violations."
Russian President Vladimir Putin announced last week that Russia would boost its nuclear arsenal by 40 missiles. Previously, Russian officials denounced the US for attempting to spark an arms race after the Pentagon announced plans to place heavy military equipment in European countries bordering Russia.
In an interview in March, Putin said that he had ordered Russia's nuclear arsenal to be placed on high alert following the Russian annexation of Crimea.
Work said that modernisation of the US's nuclear forces was expected to cost an average of $18bn (£11.4bn) a year from 2021 to 2035.
"Without additional funding dedicated to strategic forces modernisation, sustaining this level of spending will require very, very hard choices and will impact the other parts of the defence portfolio," Work said.