MEXICO CITY — Mexico is welcoming the passage by the U.S. Senate of an immigration bill that could offer a path to citizenship for millions of immigrants. But it also expressed concern that some of the security measures that form part of the reform could affect the relationship between the two countries.

The Foreign Relations Department said in a statement Thursday that approval of the bill could offer a chance for millions of Mexicans living in the United State to improve their lives.

It added, however, that some of the measures "move away from the principles of shared responsibility and neighborliness."

The bill includes adding 20,000 U.S. Border Patrol agents, doubling their number along the border with Mexico, and completing 700 miles of fencing.

It now goes to the Republican-controlled House.