A female employee of a U.S. consulate in Mexico, along with her U.S. husband and the husband of another consular employee, have been killed by unidentified murderers, the White House said on Sunday.

President Barack Obama was "deeply saddened and outraged" by the news of the murders of three people associated with the U.S. Consulate General in Ciudad Jurez, Mexico, said White House spokesman Mike Hammer in a statement.

Hammer gave no more details on the murders. Reports here quoted a U.S. official as saying that the three victims were killed in drive-by shootings on Saturday afternoon in Ciudad Juarez, where some 2,600 people were killed last year in drug-related violence.

"We will continue to work with Mexican President Felipe Calder and his government to break the power of the drug trafficking organizations that operate in Mexico and far too often target and kill the innocent. This is a responsibility we must shoulder together," said Hammer.

In light of the situation in Mexico, U.S. State Department on Sunday issued travel warning to inform Americans traveling to and living in Mexico of concerns about the security situation in Mexico.

The State Department has also authorized the departure of the dependents of U.S. government personnel from U.S. consulates in the Northern Mexican border cities of Tijuana, Nogales, Ciudad Juarez, Nuevo Laredo, Monterrey and Matamoros until April 12.