From Sahih Bukhari (Hadith 598):
Narrated Jabir:`Umar came cursing the disbelievers (of Quraish) on the day of Al-Khandaq (the battle of Trench) and said, "I could not offer the `Asr prayer till the sun had set. Then we went to Buthan and he offered the (`Asr) prayer after sunset and then he offered the Maghrib prayer
Reference: Bukhari 598