Washington ? Long-awaited climate change legislation was put on hold by its authors Saturday when a dispute over immigration politics and Senate priorities threatened to unravel a months-long bipartisan effort.

Voicing regrets, Sen. John Kerry said Saturday he is postponing the much anticipated unveiling of comprehensive energy and climate change legislation scheduled for Monday.

The Massachusetts Democrat made his announcement after a key partner in drafting the bill, Republican Sen. Lindsey Graham of South Carolina, threatened to withhold support if Senate Democratic leaders push ahead first with an immigration bill.