SAN DIEGO — The field to unseat U.S. Rep. Duncan Hunter, who is running for re-election while under indictment on corruption charges, is becoming crowded.

On Tuesday, Sen. Brian Jones, R-Santee, launched his candidacy for the California’s 50th Congressional District seat.

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Jones said he entered the race to "provide a trusted, conservative voice" for the East County district, which is currently represented by Rep. Duncan Hunter, R-Alpine. Prior to serving as a state senator, Jones served in the Assembly and as a member of the Santee City Council.

"In Santee, we proved that conservative government policies work," Jones said. "We created vibrant residential, commercial and retail development by reducing regulations and keeping taxes low, and funded the recreational and public safety services the public deserves by contracting out services."

Former Congressman Darrell Issa ended his political retirement on Thursday when he announced he is seeking the seat held by fellow Republican and longtime-U.S. Rep. Duncan Hunter.

Issa was joined by El Cajon Mayor Bill Wells, Temecula Mayor Matt Rahn, former Escondido Mayor Sam Abed and former U.S. Navy SEAL Larry Wilske, who were all running for the seat before the announcement. All four candidates elected to drop out of the race and throw their support behind Issa, who also received an endorsement from San Diego County Supervisor Dianne Jacob.

Also running for Hunter’s seat is Larry Wilske, a retired Navy SEAL and Republican.

Last month, former San Diego City Councilman and Reform California Chairman Carl DeMaio also entered the race for the only Republican-held congressional seat in San Diego County.

"Darrell Issa epitomized what is wrong with establishment California Republican politicians when he fled his own district rather than fighting for it and his constituents, and enriched himself by taking more than $645,000 of campaign cash from unsuspecting donors and putting it into his personal account,"said a spokesperson for the DeMaio campaign.

Hunter won a sixth term last November, defeating Democratic candidate Ammar Campa-Najjar with 51.7% of the vote.

Ammar Campa-Najjar is once again vying for Hunter’s seat in a race that has grown to five contenders and could potentially unseat the embattled congressman.

On Wednesday, the Campa-Najjar campaign also released a statement to Issa entering the race for California’s 50th Congressional district:

“Issa entering the race proves that Hunter is vulnerable and we're viable, and that Washington insiders are scrambling to find somebody who could effectively challenge our campaign. […] When I think about the working families, I grew up around in East County, the last person on earth who would understand their day-to-day struggles is Darrell Issa."

Currently, Campa-Najjar is the Democrats’ best hope of flipping the seat in 2020.

In a statement, Hunter's campaign said: 

"He is running for re-election so that he may continue to important work he is doing to support President Trump and to work on the issues that are important to him and his constituents. Congressman Hunter looks forward to earning their support again in 2020."

Hunter’s trial is slated to begin early next year in federal court. The state primary is scheduled for March 3.