Delete API (ES ver1.7) by regexp

I'm trying to delete one part of documents in an index by using regexp api but I can't.

The command is as follows.
curl -XDELETE 'http://localhost:9200/index/type/_query' -d '{"query":{"regexp":{"_id":"#document_tag"}}}'

I use ES ver 1.7

I wonder if "_query" is not available.
Is there way to delete?

Thank You and Best Regards.