Sen. John McCain (R-AZ) speaks with reporters ahead of the party luncheons on Capitol Hill in Washington, U.S., September 19, 2017. REUTERS/Aaron P. Bernstein

WASHINGTON (Reuters) - U.S. Senator John McCain said on Friday that he would vote against a new Republican bill to dismantle Obamacare if it is brought onto the Senate floor next week, in a new setback for the proposal.

“I cannot in good conscience vote for the Graham-Cassidy proposal,” McCain said in a statement about the bill sponsored by Senators Lindsey Graham and Bill Cassidy. McCain said he could not support the bill not knowing how much it would cost and how it would affect insurance coverage, adding that he believed both parties could do better if they work together on legislation.