diff --git a/library/ecp.c b/library/ecp.c
index 1cfd4b1..5ad6863 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1128,7 +1128,7 @@
     /* Generate l such that 1 < l < p */
     do
     {
-        mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );
@@ -1527,7 +1527,7 @@
     /* Generate l such that 1 < l < p */
     do
     {
-        mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &l, p_size, f_rng, p_rng ) );
 
         while( mbedtls_mpi_cmp_mpi( &l, &grp->P ) >= 0 )
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &l, 1 ) );