Burns had blocked action on the nominees over concerns that the voting process for overseas troops is too complex and time-consuming for ballots to arrive on time. A Senate tactic called a hold allows lawmakers to stall nominations indefinitely.
Burns spokesman Derek Hunter said Thursday the senator lifted his holds because the Pentagon pledged to "do whatever is necessary" to put a new voting system in place by November.
A Pentagon spokesman, Lt. Col. Jeremy Martin, said the department is committed to creating the new voting system in time for local governments to transmit ballots electronically to military serving abroad so that their votes can be counted.
"The Department of Defense is aggressively working to ensure that all service members and their families serving around the world will be able to receive their ballots electronically and have an opportunity to vote for the candidate of their choice in the upcoming November election," Martin said.
The Defense Department also agreed to track military voting rates in the upcoming election to assess how many members of the military are voting, Burns' office said. A Senate Armed Services Committee hearing on the issue also is expected, Hunter said.
Under the proposed system, absentee military voters could download and print the ballots and return them by mail. Under the current system, members of the military must contact local officials by regular mail and request a ballot, which is then mailed to them. The voter then must fill out the ballot by hand and send it back to his or her state, also by regular mail.
Burns, who is running for re-election, said he would block the Defense Department nominations earlier this week. He said the Pentagon did not appear serious about implementing the new voting system, despite $2.5 million appropriated for it earlier this year.