The long-awaited legislation from Senators Richard Burr and Dianne Feinstein, the top Republican and Democrat on the Senate Intelligence Committee, may be introduced as soon as next week, one of the sources said.

It would expose companies like Apple Inc, which is fighting a magistrate judge's order to unlock an iPhone connected to the mass-shooting in San Bernardino, California, to contempt of court proceedings and related penalties, the source said.

Senators are expected to circulate the draft bill among interested parties next week and hope to introduce it soon after, though a timetable is not final, the source said.

The Senators' proposal would not seek criminal penalties, as some media reports have stated, the sources said.