Interesting. Could also be that the US wants to get rid of competitors and preparing the ground for a more 'favorable' supplier.
The United States imposed sanctions on the Minsk Wheel Tractor Plant and three Chinese enterprises for allegedly transferring missile technology to Pakistan.
Pakistan was the most American friendly state in the area, among India China Iran, but things change it seems...
https://www.state.gov/u-s-imposes-sanctions-on-suppliers-to-pakistans-ballistic-missile-program/
Discussion
Probably that's it.