President Trump received a New Year’s Eve security briefing, less than 12 hours before the United States rings in 2018.

"The president has been briefed on security measures that are being taken by federal, state and local authorities to help ensure a safe and festive New Year's Eve,” White House spokeswoman Helen Ferre said Sunday afternoon. “We will continue to monitor throughout the night."

The statement comes on the heels of a deadly shooting outside of Denver, Colo., that left a Douglas County deputy dead and four other deputies wounded. Two civilians were also wounded, and the alleged gunman is also believed to have been shot dead.

In Houston, a man was arrested by local police early Sunday morning for disorderly conduct. Houston police say they found an AR-15, a shotgun, a handgun, and many rounds of ammunition in the suspect's room, which overlooked a planned New Year’s Eve celebration in downtown.

Cities nationwide have said they are stepping up security to prepare for New Year’s Eve.

In New York City, police said there will be additional law enforcement officers in the wake of two terror attacks that occurred in the city earlier this year.