Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 14
Sanskrit:
यमाहुर्वासुदेवांशं हैहयानां कुलान्तकम् ।त्रि:सप्तकृत्वो य इमां चक्रे नि:क्षत्रियां महीम् ॥ १४ ॥
ITRANS:
yam āhur vāsudevāṁśaṁhaihayānāṁ kulāntakamtriḥ-sapta-kṛtvo ya imāṁcakre niḥkṣatriyāṁ mahīm
Translation:
Learned scholars accept this Paraśurāma as the celebrated incarnation of Vāsudeva who annihilated the dynasty of Kārtavīrya. Paraśurāma killed all the kṣatriyas on earth twenty-one times.