last year, the allies agreed to sign the plan in january. but they delayed it despite north korea’s escalating missile and nuclear threats, prompting speculation that they were at odds over the scope of a counterstrike.앞쪽은 문장 구조랑 해석이 되는데요, prompting speculation that they were at odds over the scope of a counterstrike.
뒷 부분이...ㅜㅜ prompting 이 동명사 인가요?? threats를 꾸며주는??

그리고 speculation that 에서 that 은 ??

아,,,, 너무 답답하네요 ㅜㅜ

친절한 설명 좀 부탁드리겠습니다

감사합니다