MEXICO CITY (AP) — Mexico's lower house of Congress has approved a labor law reform aimed at ensuring workers can freely vote for their union representation and contracts.

The changes are needed to win approval of the new U.S.-Mexico-Canada trade agreement, which was negotiated to replace the old NAFTA accord.

Mexico's labor movement has long been stymied, and wages kept low, by pro-government unions that sign contracts and organize plants behind workers' backs.

The bill approved late Thursday now goes to the Senate. It requires secret-ballot union votes and proof of workers' consent for contracts.

President Donald Trump's daughter Ivanka tweeted Friday: "Mexican lawmakers passed a landmark labor reform bill clearing the way for the new US-Mexico-Canada Agreement (USMCA) to replace the job killing NAFTA."