American Music Awards

The singer said music executives Scooter Braun and Scott Borchetta would not let her perform songs from her past albums, which they own the rights to.

She said a Netflix documentary about her life had also been put in jeopardy.

Borchetta and Braun's Big Machine Records said Swift's statement was "based on false information".

Swift made the allegations in a statement posted to Twitter with the caption: "Don't know what else to do."

The star won four trophies, including artist of the year, making her the ceremony's most-decorated female ever.

She now holds 23 AMAs, beating a record previously held by Whitney Houston.

Swift, who recently broke years of political silence to declare support for two Democrats, again urged fans to take part in the US mid-term elections.

Accepting artist of the year, she said: "This award, and every single award given out tonight, were voted on by the people.