Definition: In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].
Input: Washington (CNN) The Pentagon has accused Russia of intentionally violating an agreement intended to prevent accidents in the skies over Syria, following a recent unsafe encounter between US F-22s and Russian Su-25 jets. "Russia is failing to genuinely de-conflict airspace in Syria. Some of these incidents are not mistakes," Chief Pentagon Spokesperson Dana W. White told CNN. "We are working to address this issue at the highest levels," she added. The Pentagon's statement comes just days after Secretary of Defense Jim Mattis said it was unclear why the Russians were violating the agreement, which separates Russian and US-led coalition forces operating in Syria.The Pentagon told CNN: "Russia is failing to genuinely de-conflict airspace in Syria. Some of these incidents are not mistakes"Last week Russia denied its planes crossed the de-confliction line 
 Question:"As far as going further into the western part, or the interior parts of the -- of _, I'm not prepared and ready to address that," Dillon said.

Syria