Syria — (CNN) -- The United States has increased contacts with Syrian opposition officials in recent week, a senior U.S. official said Friday.

The official explained that "the U.S. and others are playing more of an advisory role to the opposition now." Underpinning those increased contacts with the opposition is the effort to begin to plan for the post-Assad regime.

Still, any action so far stops short of arming the opposition. The chairman of the joint chiefs of staff said Friday that lethal support is not being discussed.

"We have been discussing a range of options for some time. Among them would be assisting the opposition," Gen. Martin Dempsey said in a news conference in San Francisco. "I've never heard any discussion of assisting them with lethal support. That is to say, the discussions that I've been involved with were about providing non-lethal support."

U.S. officials clearly are talking to those who have spoken to defectors and have spoken directly with opposition leaders, but don't want to offer a lot of detail. The official would say only that "we are sharing perspectives." Part of this, he said, involves talking about the dynamics of the situation and the potential "end game" and, he adds, "talking about how the opposition might be able to achieve their goal more quickly."

That includes vetting opposition forces and looking at how various groups might be able to "coalesce after Assad goes."

The discussion, the official told CNN, includes transition goals.

The official says it's not clear yet if U.S. policy would be to maintain the current Syrian military and government structure, to a large extent to try to avoid what happened in Iraq. And as he says, the United States might not have a voice in that anyway.