However, Reid, of Nevada, said Lieberman's support of Republican presidential candidate and friend Sen. John McCain of Arizona raised "serious concern," The Hill reported.

Reid and Lieberman, chairman of the Senate Homeland Security and Governmental Affairs Committee, met to discuss Lieberman's future as the committee's leader.

"While I understand that Senator Lieberman has voted with Democrats a majority of the time, his comments and actions have raised serious concerns among many in our caucus," Reid said in a statement. "I expect there to be additional discussions in the days to come, and Senator Lieberman and I will speak to our caucus in two weeks to discuss further steps."

Lieberman told reporters he wanted to review his options.

"I want to spend some time in the next few days thinking about what Senator Reid and I have discussed and what my options are at this point," he said.

Despite his open support for McCain, Lieberman said he "completely agreed" with President-elect Barack Obama "that we must now unite to get our economy going again and to keep the American people safe."

"That is exactly what I intend to do with my colleagues here in the Senate in support of our new president," he said. "And those are the standards I will use in considering the options that I have before me."