The Senate Foreign Relations Committee advanced the nominations of five senior diplomats, including former White House adviser Samantha Power for UN ambassador and former State Department spokeswoman Victoria Nuland for assistant secretary of state for Europe.
Three senators on the 18-member committee voted against Power, and two voted against Nuland.
Power faced scrutiny during her confirmation hearing over comments she made as a journalist and human rights campaigner perceived as critical of the US or Israel.
Nuland was questioned by several Republican senators over what she knew about last year's deadly Benghazi attack.