US Sen. Dianne Feinstein (D-Calif.) has died at the age of 90, following a number of health scares, reports said Friday.

Feinstein was the oldest member of the Senate and had announced plans to retire at the end of her term.

Her death was first reported by ABC7 Insider. NBC News also reported her death, citing two sources familiar with the matter.

Her cause of death has not yet been confirmed.

She had faced calls for her resignation in recent years over concerns about her health.

This is a developing story, check back for updates.