BY ANADOLU AGENCY APR 29, 2020
Russia on Wednesday warned that a low-yield U.S. ballistic missile strike would be seen as a nuclear attack by Moscow and would be responded to accordingly.

Speaking at a video conference in the capital Moscow, Foreign Ministry spokeswoman Maria Zakharova said a recent report by the U.S. Department of Defense on deploying low-yield submarine-launched ballistic missile warheads did not go unnoticed by Russia.

She slammed the U.S. move as "dangerous," an "element of destabilization" and a "purposeful blurring between non-strategic and strategic weapons," warning that it would lead to a "lower threshold and an increase in the threat of nuclear conflict."

"I would like to stress that any attack using a U.S. submarine-launched ballistic missile, regardless of its characteristics, will be perceived as a nuclear-weapon attack. Those who want to speculate about the flexibility of the American nuclear potential should understand that according to the Russian military doctrine, such actions will be considered a foundation for retaliatory use of nuclear weapons by Russia," she said.

On April 24, the U.S. Pentagon announced that the U.S. Navy had fielded the W76-2 low-yield submarine-launched ballistic missile (SLBM) warhead to deter Russia's and China's nuclear power.
Source:
https://www.dailysabah.com/world/europe/russia-threatens-us-of-nuclear-response-in-case-of-ballistic-missile-attack