“These barbaric slaughters are an assault upon our communities, an attack upon our nation, and a crime against all of humanity,” the president said.
The king and crown prince conveyed "deepest and sincere condolences" to the victims and the American people as whole, wishing speedy recovery to the injured.
"We cannot let those killed in El Paso, Texas, and Dayton, Ohio, die in vain," Trump said.
Assistant Police Chief Matt Carper named the gunman as Connor Betts, a 24-year-old white male from Bellbrook, Ohio, and said his sister Megan Betts, 22, was among those killed.
The attack came only hours after a shooter opened fired in a Walmart in El Paso, Texas, killing 20 people.