LOS ANGELES (AP) — Democrat T.J. Cox edged ahead of Republican U.S. Rep. David Valadao following an updated vote count Monday in a House race in California’s Central Valley, with more votes still to be counted.

Cox, who trailed since election night, pulled ahead by 438 votes in the 21st Congressional District that cuts through four counties in the state’s interior farm belt.

The Associated Press had declared Valadao the winner but votes that have been counted since Nov. 6 steadily narrowed the race, and the AP retracted its race call after Cox took the lead.

It’s unclear how many votes remain to be counted. Counties have until Dec. 7 to complete their tallies.

Democrats already have seized six GOP-held House seats in California, delivering another blow to California’s long-struggling Republican Party. If Cox prevails, Democrats will hold a 46-7 advantage in the state’s largest-in-the-nation congressional delegation.

Valadao’s seat and the other six already won by Democrats are districts Hillary Clinton carried in the 2016 presidential contest. Four of them are partially or wholly in Orange County, once a Republican stronghold in Southern California.

Valadao carried his district by a wide margin in 2016, even though registration numbers favor Democrats.

Cox made the race a referendum on Valadao’s support for President Donald Trump.

Valadao, in a tip to the district’s heavy Hispanic population, had touted his support for a way to keep in the country people who were brought to the U.S. illegally when they were children.

In a statement after taking the lead, Cox said: “Here in the Central Valley, we are often underestimated and counted out.”

Valadao’s campaign could not immediately be reached for comment.