From JPost:
The IDF General Staff postponed the expansion of ground operations in south Lebanon late Wednesday night, after the security cabinet earlier in the day approved a plan for a widened offensive that would take the army to the Litani River, over 20 kilometers from the border, and beyond, in an effort to prevent the incessant Katyusha rocket attacks on northern Israel.
The troops were already rolling late Wednesday when they were ordered to halt. It appears heavy US pressure delayed the offensive to allow diplomacy to run its course. A senior minister said Wednesday that Israel might delay the expansion for 2-3 days for that purpose.
I would think the last thing Olmert needs is any more encouragement to delay, agonize, and wobble.