ENOfficial
Anas reported that the Messenger of Allah (ﷺ) observed Qunut for one month invoking curse upon some tribes of Arabia (those who were responsible for the murders in Bi'r Ma'una and Raji'), but then abandoned it.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا عَبْدُ الرَّحْمَنِ، حَدَّثَنَا هِشَامٌ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَنَتَ شَهْرًا يَدْعُو عَلَى أَحْيَاءٍ مِنْ أَحْيَاءِ الْعَرَبِ ثُمَّ تَرَكَهُ .
sunnah.com