Allied forces attacked her car at a checkpoint in Baghdad.
Literal
Allied-forces [topic-は] Baghdad [possessive-の] checkpoint [at-で] her car [object-を] attacked.
同盟軍 ('allied forces') is military vocabulary. 検問所 (けんもんじょ, 'checkpoint') is the specific term for a military/police checkpoint. 襲撃した (しゅうげきした, 'attacked, raided') is the forceful verb. バグダッド is Baghdad. A news-style military incident report.