Cyclotomic Integer with a Given Norm?

["B.Y." <by@precision.moscito.org>]

Dear Sirs (and Mesdames):

	Can someone tell me if there is a ready and easy way to decide 
with PARI whether there exists an integer $a$ in a cyclotomic field 
$Q(\zeta_n)$ with a given norm $p$, where $p$ is a prime number?

	Thanks for any tips or pointers to knowledge.

						Sincerely, Bo-Yin Yang