A second woman came forward Friday with claims that she had been sexually assaulted by Lt. Gov. Justin E. Fairfax of Virginia, intensifying the weeklong political crisis in the state and leading top fellow Democrats to call for Mr. Fairfax to resign.

The woman, Meredith Watson, accused Mr. Fairfax of raping her in 2000 while they were students at Duke University, saying in a statement that his actions were “premeditated and aggressive” and demanding that he step down immediately.

Ms. Watson spoke out two days after Vanessa C. Tyson, a political science professor from California, said she was assaulted by Mr. Fairfax during the 2004 Democratic National Convention in Boston.

By Friday night, Mr. Fairfax was facing a wave of calls for his resignation. Democrats in the Virginia House and Senate urged him to step down, saying he “could no longer fulfill his duties to the commonwealth,” as did the Virginia Legislative Black Caucus, a powerful bloc within the General Assembly. Patrick Hope, a Democrat in the Virginia House, said he would introduce articles of impeachment on Monday if the lieutenant governor had not resigned.