An Iranian-born woman who blogged about surviving in a world filled with "injustice and diseases" opened fire at YouTube's California headquarters because she was angry at a site she believed was suppressing her videos, police said on Wednesday.

In a series of Persian and English-language online postings, Nasim Najafi Aghdam, 39, had railed against the video-sharing site owned by Alphabet Inc.'s Google before wounding three people and killing herself on Tuesday at its offices in San Bruno, just south of San Francisco.

In an English-language video posted to her YouTube account before the channel was deleted on Tuesday, Aghdam said: "I am being discriminated. I am being filtered on YouTube."