Escape jinja2 syntax in a jinja2 template

I serve dynamic pages from Jinja2 templates in Flask. Now I am defining client-side templates in say, Jinja2-clone Nunjucks inside a script tag. Problem is, the client-side templates has syntax like <% %> that Flask's Jinja2 interpreter may interpret instead of rendering verbatim.

How can I make the entire block of scripts render verbatim?

You can disable interpretation of tags inside a {% raw %} block:

{% raw %}

Anything in this block is treated as raw text,
including {{ curly braces }} and
{% other block-like syntax %}

{% endraw %}

See the Escaping section of the template documentation.