WASHINGTON - PRESIDENT Barack Obama called on Sunday for strengthening higher education so that the United States could lead the world in college degrees in a decade.

'In an economy where jobs requiring at least an associate's degree are projected to grow twice as fast as jobs requiring no college experience, it's never been more essential to continue education and training after high school,' Mr Obama wrote in an op-ed piece in The Washington Post.

MEXICO CITY - THREE Mexican federal police officers were killed and 18 were wounded on Saturday in attacks attributed to the La Familia Michoacana drug cartel on at least six different cities, police said.

The onslaught on six federal police (PFP) bases in the western state of Michoacan was seen as retribution for the arrest on Friday of top La Familia member Arnoldo Rueda.

WASHINGTON - US SECRETARY of State Hillary Clinton is set to return to the world stage this week when she delivers a major policy speech and resumes foreign travel after a she was sidelined by a broken elbow.

Mrs Clinton gets her second wind as she marks her first six months in a job where analysts say she treads a fine line between showing loyalty to President Barack Obama, a former political rival, and imposing herself as chief US diplomat. Mrs Clinton has walked the tightrope well, many add.