Authorities stepped up security at the PEN American Center awards in New York City Tuesday night, following Sunday's attack in Texas where two gunmen opened fire at an event to draw the Prophet Muhammad. Police, counterterrorism units and police dogs stood guard outside the American Museum of Natural History, where the event was held. French satirical newspaper Charlie Hebdo, which came under attack by Islamist gunmen earlier this year, received the PEN/Toni and James C. Goodale Freedrom of Expression Courage Award. "Charlie Hebdo's current staff have persisted, and tonight's award reflects their refusal to accept the curtailment of lawful speech through violence," PEN President Andrew Solomon said at the gala. The decision to award Charlie Hebdo sparked controversy, prompting six writers to withdraw from the event an more than 100 members to sign a letter petitioning the honor.