Rep. Mark DeSaulnier, D-Concord, who has been hospitalized with pneumonia after fracturing a rib in a running accident, is in critical condition.

DeSaulnier was originally listed in serious but stable condition, but his health has taken a turn for the worse, according to a statement Saturday afternoon from his office. He is being treated at a hospital in the Washington, D.C., area.

DeSaulnier, a 67-year-old cancer survivor and avid runner who has completed 21 marathons, tested negative for COVID-19.

“Unfortunately, Congressman DeSaulnier’s condition has deteriorated and he is in critical condition. The doctors are doing everything they can to care for the congressman. Mark’s family and staff appreciate your thoughts and prayers during this very difficult time,” said his chief of staff, Betsy Arnold Marr.

DeSaulnier fell and fractured his rib near a U.S. House office building during one of his regular runs in the capital.

DeSaulnier has served in Congress since 2015, and previously as a state senator, state assemblyman, Contra Costa County supervisor, mayor of Concord, and on the Concord City Council.