WASHINGTON — President Bush and the Democratic-controlled Congress careened closer to a full-blown legal showdown over the firing of federal prosecutors yesterday as a House subcommittee voted subpoenas for top administration officials in defiance of the White House.

“After two months of stonewalling, shifting stories, and misleading testimony, it is clear that we are still not getting the truth about the decision to fire these prosecutors and its coverup,” said Rep. Linda Sanchez, a Democrat of California.

In response, an unyielding White House threatened to rescind its day-old proposal for top strategist Karl Rove and other officials to answer lawmakers’ questions away from the glare of television lights and not under oath. “If they issue subpoenas, yes, the offer is withdrawn,” said White House spokesman Tony Snow. Democrats “will have rejected the offer,” he said.

Rep. John Conyers, who is the chairman of the House Judiciary Committee, repeatedly suggested there was room for negotiations in a confrontation that has threatened Attorney General Alberto Gonzales’s hold on his job and forced his chief of staff to resign.