Seth Williams (235186)

(CNN) — The district attorney of Philadelphia pleaded guilty to federal bribery charges Thursday and resigned effective immediately, federal officials said.

Seth Williams, who was twice elected as Philadelphia’s district attorney, pleaded guilty to one count of travel and use of interstate facilities to promote and facilitate bribery contrary to Pennsylvania law, according to acting New Jersey US Attorney William E. Fitzpatrick.

As part of the plea agreement, prosecutors will move to dismiss the remaining 28 charges. Williams agreed to resign as Philadelphia district attorney and he faces up to five years in prison. In addition, as part of the plea agreement, Williams must forfeit $64,878.22 from bribes and fraud proceeds and admit he committed all the offenses for which he was indicted.

“Today, Mr. Williams admitted all of that conduct,” Fitzpatrick said. “Williams owed the public a duty to act according to the highest legal and ethical standards. Seth Williams breached that trust; he abused his power; and he will now be held accountable for his actions.”

Williams was initially accused of accepting bribes between 2010 and 2015 to use his position to help two business owners, according to the indictment by the United States Attorney’s Office for New Jersey.

In exchange for bribes including a 1997 Jaguar XK8 convertible, 16 round-trip airline tickets, $9,000 in cash and checks and a $6,381 vacation to the Dominican Republic, Williams made calls to help one business owner avoid security screenings at the airport when returning from foreign travel and attempted to assist with the criminal case of a friend of the business owner, court documents say.

The second business owner, prosecutors said, was appointed as a special adviser to the district attorney and issued an official badge. Williams also sent a letter to the California Department of Alcoholic Beverage Control before a hearing on the business owner’s liquor license in that state, according to court documents.

Prosecutors also said Williams used money from his mother’s pension and Social Security payments to pay for his own personal expenses instead of paying for her nursing home costs, and when his mother’s friends gave him $10,000 to help cover the nursing home expenses, court documents say, Williams spent that on himself as well.

Additionally, court documents said Williams used federal narcotics law enforcement vehicles to transport himself, family and friends on personal trips.

The trial began two weeks ago, and Williams had previously entered a not guilty plea.

“Seth Williams accepted responsibility for his actions today,” Williams’ attorney, Trevan Borum, said in a statement. “He deeply regrets letting down the citizens of Philadelphia and the hardworking men and women in the Philadelphia District Attorney’s Office.”

“The assistant district attorneys and professional staff of the Philadelphia District Attorney’s Office are among the finest in the country,” Kathleen Martin, first assistant for the Philadelphia District Attorney’s Office, said in a statement. “I could not be more proud of how my hardworking colleagues have conducted themselves in light of the investigation and prosecution of Mr. Williams.”

Williams was ordered detained until his October 24 sentencing, according to the New Jersey US Attorney’s office.