diff --git a/lib/cm-impl.h b/lib/cm-impl.h
index 9146df69a5e6c1a5fd15395d8da1a270ffd00055..b71b6c0174547b5771ed9b4f380ba7f9e808d418 100644
--- a/lib/cm-impl.h
+++ b/lib/cm-impl.h
@@ -91,9 +91,6 @@ extern void cm_nt_factor (uint_cl_t d, uint_cl_t *factors,
 extern uint_cl_t cm_nt_largest_factor (uint_cl_t n);
 extern unsigned int cm_nt_mpz_tonelli_generator (mpz_ptr q, mpz_ptr z,
    mpz_srcptr p);
-extern void cm_nt_mpz_tonelli_with_generator (mpz_ptr root,
-   mpz_srcptr a, mpz_srcptr p, unsigned int e, mpz_srcptr q,
-   mpz_srcptr z);
 extern void cm_nt_mpz_tonelli_si_with_generator (mpz_ptr root,
    const long int a, mpz_srcptr p, unsigned int e, mpz_srcptr q,
    mpz_srcptr z);
diff --git a/lib/nt.c b/lib/nt.c
index 9c02b08e66a82795aaa4b812e3efa92d275b8c6a..b4586675bd98d1023ecd1bd8773704a93855e335 100644
--- a/lib/nt.c
+++ b/lib/nt.c
@@ -25,6 +25,8 @@ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 static void tree_gcd (mpz_t *gcd, mpz_srcptr n, mpz_t *m, int no_m);
 static int miller_rabin (mpz_srcptr n);
+static void cm_nt_mpz_tonelli_with_generator (mpz_ptr root, mpz_srcptr a,
+   mpz_srcptr p, unsigned int e, mpz_srcptr q, mpz_srcptr z);
 
 /*****************************************************************************/
 
@@ -322,7 +324,7 @@ unsigned int cm_nt_mpz_tonelli_generator (mpz_ptr q, mpz_ptr z,
 
 /*****************************************************************************/
 
-void cm_nt_mpz_tonelli_with_generator (mpz_ptr root, mpz_srcptr a,
+static void cm_nt_mpz_tonelli_with_generator (mpz_ptr root, mpz_srcptr a,
    mpz_srcptr p, unsigned int e, mpz_srcptr q, mpz_srcptr z)
    /* Compute a square root of a modulo p by the Tonelli-Shanks algorithm,
       see Cohen93, Algorithm 1.5. */