WASHINGTON — The Senate Intelligence Committee on Tuesday voted 12 to 3 to confirm John O. Brennan as director of the Central Intelligence Agency after the White House agreed to provide more information on the legal basis for targeted killings of Americans abroad who are believed to pose a terrorist threat.

The vote, in a closed committee meeting, showed that there was substantial bipartisan support for Mr. Brennan, a 25-year C.I.A. veteran who has most recently been President Obama’s top counterterrorism adviser and has overseen the expansion of strikes by the C.I.A. and the military in Pakistan, Yemen and Somalia.

The three no votes were cast by Republicans, including the vice chairman, Senator Saxby Chambliss of Georgia. Four Republicans voted in favor of confirmation. Senator Rand Paul, Republican of Kentucky, said he would filibuster the nomination after receiving a letter from Attorney General Eric H. Holder Jr. that declined to rule out lethal drone strikes in the United States in “extraordinary circumstances” like a “catastrophic attack” along the lines of Pearl Harbor or Sept. 11, 2001. But it appeared likely that the nomination would get the 60 votes required to end the filibuster, possibly as early as Thursday.

While Mr. Brennan, 57, has been widely expected to win confirmation, senators of both parties have used his nomination to try to pressure the White House into disclosing information it has previously declined to give Congress.