"Break open" - what is "open"? An adverb, noun, adjective or verb?

In the phrases "break open" and "break [sth.] open", is "open" an adjective or an adverb? Is it an adverbial or a complement?

For example:

The pods broke open and the seeds scattered on the wind.

The police broke open the door.

The burglars broke the locked safe open.

Solution 1:

[EDIT - post comments] Before reading my answer, please review the links John Lawler provided in the comments above. It's here for convenience: https://english.stackexchange.com/search?q=user%3A15299+phrasal+verb I am not so convinced my answer is sufficient based on his and user:deadrat 's comments below and those above, but I'm leaving my answer here as an example of what seems to be a common misunderstanding, an over simplification, of a more complex subject.

All those forms are based on "broke open," making open an adverb. How was it broken? It was broken open.

Similar constructions, e.g.:

The police bashed in the window.
The police broke up the protests.

( Not sure, if this is considered a compound form ?)

But if you had, say:

The guard closed the open door.

then open would be an adjective. What kind of door? An open door.