WASHINGTON (AP) _ President Clinton exhorted Americans today to join a nationwide volunteer campaign and make Monday's Martin Luther King Jr. holiday ``a day on, not a day off.''

``To honor what would have been Dr. King's 70th birthday, I urge all Americans to rise to the highest calling in our land _ the calling of active citizenship,'' the president said in his weekly radio broadcast from the Oval Office.

In conjunction with the Monday holiday, the White House released a report from Clinton's long-floundering initiative on race relations. The report, titled ``Pathways to One America in the 21st Century,'' is meant to serve as a ``a guide to some of our communities' best ways to building that elusive `one America': one neighborhood, one school system, one workplace at a time,'' Clinton said.

The administration's Americorps national service program is organizing projects nationwide _ such as painting schools, reading to children, cleaning up parks _ to mark the King holiday on Monday, a day off for federal workers and many in the private sector.

Clinton publicized the Americorps Web site (www.americorps.org) and urged Americans to log on and sign up for projects in their area. Donating blood is another good way to observe the holiday, he said.

``We believe that this national holiday should be a day on, not a day off,'' Clinton said. ``For as Dr. King once said, `Life's most persistent and urgent question is what are you going to do for others?'''