Russia has had a strategic ABM system around Moscow since the 60s. The system, which has at various times deployed up to 100 nuclear armed intercept missiles, was agreed on "two sights,100 missiles each",with the SALT 1972 talks. And later amended to one sight and 100 missiles in 1974. As far as I know the thing is still operating tho its the most colossal waste of money in the Russian defense budget.
And unless they changed it the missiles themselves have warheads in the heavy mega tonnage and you have to wonder how much damage they will cause when they go off. Or if there's and accident or a theft. Its an antiquated system anyways. And one that is easily defeated.
America is developing a multi-tiered group of systems with a host of ABM systems, both theatre and strategic, either in development or limited deployment.