Amid escalating violence and IEDs, the U.S. Embassy advises against travel to the US- Mexico border and Mexico's Tamaulipas region.

The warning was issued because of "increasingly frequent gun battles" and the discovery of "improvised explosive devices (IEDs)."

Southwest Airlines posted a profit in the fourth quarter as bookings during the holidays were better than expected on the back of travel demand that remained strong and is expected to remain so. The carrier logged net income of $261 million,

A downbeat outlook tarnished an otherwise strong quarter for Southwest, which topped profit estimates on robust holiday travel.