diff --git a/python/obitools3/commands/ecopcr.pyx b/python/obitools3/commands/ecopcr.pyx
index 240930e..ed7c8b6 100755
--- a/python/obitools3/commands/ecopcr.pyx
+++ b/python/obitools3/commands/ecopcr.pyx
@@ -35,12 +35,14 @@ def addOptions(parser):
                        action="store", dest="ecopcr:primer1",
                        metavar='<PRIMER>',
                        type=str,
+                       required=True,
                        help="Forward primer, length must be less than or equal to 32")
 
     group.add_argument('--primer2', '-R',
                        action="store", dest="ecopcr:primer2",
                        metavar='<PRIMER>',
                        type=str,
+                       required=True,
                        help="Reverse primer, length must be less than or equal to 32")
 
     group.add_argument('--error', '-e',
diff --git a/python/obitools3/commands/ngsfilter.pyx b/python/obitools3/commands/ngsfilter.pyx
index b99d168..1f89638 100644
--- a/python/obitools3/commands/ngsfilter.pyx
+++ b/python/obitools3/commands/ngsfilter.pyx
@@ -42,6 +42,7 @@ def addOptions(parser):
                      metavar="<URI>",
                      type=str,
                      default=None,
+                     required=True,
                      help="URI to the view containing the samples definition (with tags, primers, sample names,...).\n"
                           "\nWarning: primer lengths must be less than or equal to 32")