US does not authorise use of long-range weapons to strike deep into Russia for several reasons, including small number of long-range ATACMS missiles - Singh

A small number of long-range ATACMS missiles and fears of escalation. These are the reasons why the US does not allow Ukraine to strike deep into Russia.
According to Censor.NET, citing Voice of America, this was stated by Deputy Spokesperson for the US Department of Defence Sabrina Singh.
"There are a limited number of ATACMS. There is no surplus of these long-range weapons. And, of course, one thing we always assess is escalation, and that's something we've been very clear about from the beginning," Singh said.
At the same time, the Pentagon spokesperson added that Ukraine has been successfully using ATACMS for combat operations in eastern and southern Ukraine. And it is there that the United States is helping them to direct their combat power.
To recap, the day before, Kirby said that the claim that Ukraine would be able to hit most military aircraft with ATACMS was false, as Russia had moved the vast majority of its aircraft inland.