US Deputy Pentagon Press Secretary Sabrina Singh reconfirmed US' position on not allowing Ukraine to strike deep inside Russia at this point.
"I want to point out what the secretary has said, there is no silver bullet that allows Ukraine to win this war. It is how all the systems work together, and how Ukraine uses them together. Ukraine is deploying all those capabilities and they are very succesful in doing it."
A very long answer for: we fear escalation with Russia.