Devibhagavatapurana 3.17.35

3.17.35

sudarśanastu tacchrutvā dadhāraikākṣaraṃ sphuṭam |
anusvārayutaṃ tacca provācāpi punaḥ punaḥ ||

Sudars’ana, too, hearing them pronounce “Klib,” “Klib” took up the one letter, “Kli” and uttered this only repeatedly, which is, in fact the prince of the root mantras of Kâma, with anusvâra omitted.