Law-enforcement officials in U.S. cities were beefing up security on Thursday after a deadly attack in New Orleans and an explosion outside a Trump hotel in Las Vegas raised fears of more threats in a month packed with large-scale public events.

Turo, the car rental app used to rent vehicles involved in both the New Years Day New Orleans attack and Las Vegas explosion released a statement Thursday saying it was "heartbroken" over the violence and working with investigators on both deadly cases.