SAN FRANCISCO (AP) — Facebook's mystery "press event" on Tuesday could reveal a more robust search feature that would intensify the competition between the social networking giant and its rival Google Inc.

Facebook is holding the event at 10 a.m. (1 p.m. EST) at its Menlo Park, Calif., headquarters. The company has not said what it plans to announce. Last week, it invited bloggers and journalists to "come see what we're building."

The company probably won't be showing off a new office building —unless it decided to make its invitation very literal.