Story highlights Democratic Sen. Dianne Feinstein is the oldest currently serving US senator

Progressives in California have grumbled over some of her recent remarks

(CNN) Sen. Dianne Feinstein is running for reelection next year -- moving to get in front of potential primary challenges from California Democrats who have urged her to be more aggressive against President Donald Trump.

The announcement that Feinstein would run was first tweeted Monday by an unverified Twitter account affiliated with Feinstein. A spokesman for Feinstein confirmed its veracity to CNN.

"I am running for reelection to the Senate. Lots more to do: ending gun violence, combating climate change, access to healthcare. I'm all in!" the tweet said.

Feinstein has been in her seat since 1992. At 84, Feinstein is the oldest senator currently serving in the chamber. She is the top Democrat on the Senate judiciary committee.

Her decision to run for reelection comes in the face of grumbling from progressives in California over some of the senator's recent remarks about President Donald Trump. Among them: She said two months ago that she hopes Trump "has the ability to learn and to change, and if he does,he can be a good president."