US missiles: Russia vows ‘tangible’ response

BBC :

Russia says the use of US long-range missiles by Ukraine will lead to “an appropriate and tangible” response.
Such an attack inside Russian territory “would represent the direct involvement of the United States and its satellites in hostilities against Russia”, a foreign ministry statement said.
President Joe Biden approved the use of the missiles on targets in Russia in a major change of US policy – two months before he is due to leave the White House.
It is not clear if his successor, President-elect Donald Trump, was consulted or whether he will stick by the decision, having promised to end the Russia-Ukraine war.