[EDITOR’S NOTE: This story has been updated with a comment from U.S. Rep. Henry Cuellar.]

LAREDO, Texas (Border Report) — A runoff election in May will determine the Democratic nominee for Texas’ 28th Congressional District after the grassroots campaign of progressive challenger Jessica Cisneros on Tuesday tested longtime border incumbent U.S. Rep. Henry Cuellar.

Both Cuellar and Cisneros on Wednesday afternoon had captured 47% of the votes. Neither received the 50% plus one vote needed for the nomination under Texas law, according to returns posted by the Texas Secretary of State’s office.

Environmentalist Tannya Benavides received 4.8%.

“This Tuesday, the 28th Congressional District spoke, and we witnessed our great Democratic system at work,” Cuellar told Border Report in a statement. “We will now move to a runoff election on May 24th and we are confident we will win. Thank you to God, my family, Imelda, Christy, and Catie, and all of our wonderful supporters who have done so much already these last few months, we are ready to keep going. I look forward to once again winning the majority of voters and come May 24th, be re-elected as the Democratic Nominee for Congress.”

In a news conference on Wednesday morning, Cisneros said voters in South Texas are signaling they “want new leadership.”

“It’s been a long night. But I’m also very excited because last night Henry Cuellar did not meet the 50% to get the Democratic nomination for Congress so that means over 50% of voters in our district want new leadership for District 28,” Cisneros said at her downtown campaign headquarters.

“It’s really exciting to see how our conversation from the people-centered policy we are running on has gotten so much momentum,” said Cisneros, a 28-year-old immigration lawyer who at one point interned for Cuellar.

Throughout Tuesday night and into the early morning hours of Wednesday, the percentage points between Cisneros and Cuellar seesawed, with each candidate at some points surpassing the 50% mark, but in the end, neither was able to hold it.

Cisneros won in Bexar County, which includes San Antonio, and Guadalupe County — both far north of the South Texas border with Mexico.

Cuellar dominated in the border counties of Starr, Zapata and Webb, which includes his hometown of Laredo.

A total of 49,586 votes were cast in the district that has over 438,000 registered voters — that means 11% of voters cast ballots.

Turnout in tiny Zapata County, located just east of Webb County, was 43% of the 7,841 registered voters. It’s a county that flipped for Donald Trump in 2020 and has grown considerably more conservative.

Cuellar, who is serving his ninth term in Congress, is a well-known moderate who often works across the aisle with Republicans, and is popular among border security organizations and the U.S. Border Patrol. He also is vice chairman of the House Homeland Security Appropriations Subcommittee, which controls spending for border security issues.

Cisneros is backed by Sen. Bernie Sanders, Alexandria Ocasio-Cortez and the Justice Democrats progressive pact.

The New York Times called this the “most competitive” of all midterm races held Tuesday in the Lone Star State.

Reporters from across the country, including CNN and the Huffington Post, attended Cisneros’ watch party at an outdoor palapa-like venue with festive Tejano music and filled with young families.

Cuellar did not host a watch party.

Cuellar has amassed a war chest over several terms in Congress, but Cisneros forced him to chip into his funds this election cycle.

Campaign reports show Cisneros has about $409,000 in reserves, while Cuellar has $1.27 million remaining.