Senator Barack Obama’s campaign on Thursday accused Senator Hillary Rodham Clinton of purposely distorting her position on the North American Free Trade Agreement, pointing to newly released White House schedules that show Mrs. Clinton attended several meetings on the trade pact while first lady.

In one meeting cited by the Obama campaign, on Nov. 10, 1993, Mrs. Clinton spoke to about 120 participants at a Nafta briefing.

On the schedule released by the National Archives on Wednesday, the meeting was described as a “Nafta Briefing Drop-By” and was closed to the press. Three other meetings in 1993 were generically described as Nafta meetings, but the schedules provided few details.

The Obama campaign pounced, eager to change the subject from race and the controversy surrounding Mr. Obama’s former pastor to questions over Mrs. Clinton’s character and experience.