Associations were stunned Monday by the mass shooting that left at least 58 people dead in Las Vegas, a city that hosts many annual meetings and trade shows year after year.

Two groups are going ahead as planned with events scheduled to start there Monday, but are closely monitoring the situation.

The American Gaming Association and Reed Exhibitions, its partner for Global Gaming Expo, will be in constant contact with local and national law enforcement and host hotel Las Vegas Sands, AGA CEO Geoff Freeman said in a statement. G2E annually attracts 26,000 attendees.

"The gaming industry is a tight-knit community, and Las Vegas is the beating heart of our operations," Freeman said. "The AGA and Reed Exhibitions will offer our full assistance as the city recovers, and we will strive to honor the victims of this tragic event."

Many thousands of people were attending a music festival on the famous Las Vegas Strip Sunday evening when a gunman—positioned high in a nearby hotel—opened fire on the crowd. More than 500 people were injured.

AGA has had staff on the ground in Las Vegas since the weekend; all had been accounted for, a spokesman said.

Twelve people were in Las Vegas preparing for the Electronic Retailing Association's convention, ERA D2C. A spokesman, Andy Schwarz, said a roll call confirmed that all are safe. D2C attracts about 2,000 attendees and is held every year in Las Vegas.

"ERA expresses its deepest sympathy and concern in the aftermath of the horrific shootings in Las Vegas," the group said in a statement. "Our host hotel, Wynn Las Vegas, is doing everything in its power to ensure the safety of its guests. With the support of ERA leadership and the Wynn Las Vegas, we are moving forward with the ERA D2C Convention Oct. 2-5 and the Moxie Awards Gala on Oct. 3."

Las Vegas is the second most popular meetings destination in the United States, after Orlando, according to Cvent, an online platform for event planning.

The Consumer Technology Association holds its massive show, CES, each January in Las Vegas. CEO Gary Shapiro tweeted, "Our hearts are with the victims of the Las Vegas shootings and their families at this tragic time. … Las Vegas is @CES, and we will always be there for the city."

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