Continued settlement building "seriously undermines Israel's security," U.S. Ambassador to the United Nations, Samantha Power, said on Friday after Washington allowed the U.N. Security Council to adopt a resolution demanding an end to settlements by abstaining from the vote.

"The United States has been sending a message that the settlements must stop privately and publicly for nearly five decades," she told the council after the vote.

"One cannot simultaneously champion expanding Israeli settlements and champion a viable two state solution that would end the conflict. One had to make a choice between settlements and separation," she said.