Not sure this is the best way, but I have managed to get the desired result set with following $args
parameters.
$args['tax_query'] = array(
'relation' => 'AND',
array(
'taxonomy' => 'category',
'field' => 'id',
'terms' => array(100),
),
array(
'taxonomy' => 'category',
'field' => 'id',
'terms' => array(105,106),
),
);