Deleting 100 rows which meets certain criteria

I am newbie to postgres/SQL.

I want to delete all rows exceeding 400 hours (10 days) and I want to
limit deletion of only 100 records at a time.

I was trying the following in PostgreSQL:

DELETE from mytable WHERE (now() - timestamp_field  > INTERVAL '400
hour' ) LIMIT 100;

Looks like DELETE syntax doesn't support LIMIT.

Is there any other way to achieve this?

thanks
Shul