Sen. Joe Lieberman (I-Conn.) said Sunday that the government of Iran was in danger of toppling and stressed that Washington should support the opposition protesters there.

"I think that everybody we spoke to thought that the green movement, the protests of the people of Iran, are very significant, and that, in some sense, a real sense, it is the beginning of the end of the repressive extremist regime in Tehran," Lieberman, who was in Jerusalem on Sunday on a recess trip through the region, said on CNN's "State of the Union."

"The question is, when does it end?"

Lieberman has traveled to Iraq, Kuwait, Afghanistan, Pakistan, Lebanon and Israel with Sen. John McCain (R-Ariz.).

"And I think we have to do everything we can not just to put economic sanctions on Iran because of their development of nuclear weapons but to support the people of Iran, to cry out against the human rights abuses, the terrible repression of the demonstrators and just the freedom of average citizens in Iran," Lieberman added.

McCain said instability in Iran also begged the need to put greater urgency on Mideast peace talks.

"I believe that this regime's days are numbered, but in the meantime, one of the dangerous aspects is that, if the Iranian government chooses to try to divert the attention of the people from their domestic situation to increasing confrontation with Israel is a real threat, and it argues for progress in the Israeli-Palestinian peace talks," McCain said.