By Jim Finkle and Joseph Menn

BOSTON/SAN FRANCISCO (Reuters) - Apple Inc computers were attacked by the same hackers who targeted Facebook Inc, but no data appeared to have been stolen, the company said on Tuesday in an unprecedented admission of a widespread cyber-security breach.

Facebook revealed on Friday that unidentified hackers traced to China had staged a sophisticated attack by infiltrating its employees' laptops, but no user information was compromised.

Apple, which is working with law enforcement to track down the hackers, told Reuters that only a small number of its employees' Macintosh computers were breached, but "there was no evidence that any data left Apple."

The iPhone and iPad maker said it would release a software tool later on Tuesday to protect customers against the malicious software used in the attacks.

Cyber-security attacks have been on the rise. In last week's State of the Union address, U.S. President Barack Obama issued an executive order seeking better protection of the country's critical infrastructure from cyber attacks.

(Reporting By Jim Finkle and Joseph Menn. Editing by Andre Grenon)