My two cents: The paragraph could use some commas, or parentheses:
The setbacks to the Minsk deal, since the rebels disavowed it by taking a strategic town they said was not covered by the truce, have prompted new calls for U.S. President Barack Obama to give Kiev lethal weapons to defend Ukraine.
The setbacks to the Minsk deal (since the rebels disavowed it by taking a strategic town they said was not covered by the truce) have prompted new calls for U.S. President Barack Obama to give Kiev lethal weapons to defend Ukraine.
