WASHINGTON  — A second woman abruptly emerged Monday to accuse Roy Moore of sexually assaulting her as a teenager in the late 1970s, this time in a locked car, further roiling the Alabama Republican’s candidacy for an open Senate seat. Leaders of Moore’s own party intensified their efforts to push him out of the race.

Anticipating a tearful Beverly Young Nelson’s allegations at a New York news conference, Moore’s campaign ridiculed her attorney, Gloria Allred, beforehand as “a sensationalist leading a witch hunt.” The campaign said Moore was innocent and “has never had any sexual misconduct with anyone.” He insisted he was in the race to stay.

In the latest day of jarring events, Senate Republican leader Mitch McConnell and Moore essentially declared open war on each other. McConnell said the former judge should quit the race over a series of recent allegations of past improper relationships with teenage girls. No, said Moore, the Kentucky senator is the one who should get out.

Cory Gardner of Colorado, who heads the Senate GOP’s campaign organization, said not only should Moore step aside but if he should win “the Senate should vote to expel him because he does not meet the ethical and moral requirements of the United States Senate.”

McConnell took a remarkably personal swipe at his party’s candidate for a Senate seat the GOP cannot afford to lose. “I believe the women,” he said, marking an intensified effort by leaders to ditch Moore before a Dec. 12 special election that has swung from an assured GOP victory to one that Democrats could conceivably swipe.

Moore, an outspoken Christian conservative and former state Supreme Court judge, fired back at McConnell on Twitter.

“The person who should step aside is @SenateMajLdr Mitch McConnell. He has failed conservatives and must be replaced. #DrainTheSwamp,” Moore wrote.

Nelson’s news conference came after that exchange and injected a new, sensational accusation in the story.

She said Moore was a regular customer at the restaurant where she worked after school in Gadsden, Alabama. One night when she was 16, Moore offered to drive her home, she said, but instead parked the car behind the restaurant and assaulted her. As she got out of the car, he warned her no one would believe because he was a county prosecutor, Nelson said. She said she quit her job the following day.