Share some before_filters between controllers

I have two parent controllers, one for an API, one for normal html pages.

class ApplicationController < ActionController::Base
    ...
end

class ApiController < ActionController::Metal
    include AbstractController::Callbacks
    ...
end

I want to share some before_filter on both controllers. I tried something like this:

class ApplicationController < ActionController::Base
    include MyFilters
end

class ApiController < ActionController::Metal
    include MyFilters
end

module MyFilters
    before_filter :filter1
    before_filter :filter2

    def filter1
    end

    def filter2
    end
    ...
end

And also this:

module MyFilters
    def self.included(klass)
        klass.before_filter :filter1
        klass.before_filter :filter2
    end

    def filter1
    end

    def filter2
    end
    ...
end

But in both cases I receive:

undefined method `before_filter' for MyFilters:Module

What is the correct way to implement this?