Neutron stars are one of the possible evolutionary end-points of high mass stars. They’re born in a core-collapse supernova star explosion and subsequently rotate extremely rapidly as a consequence of their physics. Neutron stars can rotate up to 60 times per second after born. Under special circumstances, this rate can increase to more than 600 times per second.
Source: Swinburne University of Technology Centre for Astrophysics and Supercomputing