President Donald Trump described the El Paso attack as 'an act of cowardice' and police are treating it as a possible hate crime
Two mass shootings in the United States have left 30 people dead within 24 hours, the latest such attacks in a nation torn over how to tackle gun violence.
A gunman armed with an assault rifle killed 20 people early hours on yesterday when he opened fire on shoppers at a packed Walmart store in El Paso, Texas.
Less than 13 hours later, a lone shooter killed nine people in Dayton, Ohio yesterday before being shot dead by responding police officers.
The attacker opened fire around 0500 GMT on a street in the popular bar and nightlife district called Oregon, leaving nine dead and 26 wounded.
Dayton Mayor Nan Whaley said the shooter was wearing body armour and had high-capacity magazines and extra magazines.
It was the 251st mass shooting in the US, according to the Gun Violence Archive, an NGO. It defines mass shooting as an incident in which at least four people are wounded or killed in a shooting.
Dayton deputy police chief Lieutenant Colonel Matt Carper said police were working to identify the shooter and the FBI were on the scene.
The incident came just hours after the mass shooting at a Walmart store in Texas which has reignited debate about the US epidemic of gun violence. Witnesses said the gunman appeared to be shooting at random when he opened fire around 1530 GMT.
President Donald Trump described the El Paso attack as "an act of cowardice" and police are treating it as a possible hate crime.
Footage shot with cellphones appeared to show multiple bodies lying on the ground in the store's parking lot while other footage showed terrified shoppers running out of the store as gunfire echoed.
Police chief Greg Allen confirmed that in addition to the 20 confirmed fatalities in El Paso, there were 26 wounded.
Mexican President Andres Manuel Lopez Obrador said three Mexican citizens were killed and Foreign Minister Marcelo Ebrard said six others were wounded.
News reports said the ages of victims being treated at hospitals ranged from two to 82 years.
Police said that Walmart was "at capacity" at the time of the shooting, with 1,000-3,000 customers inside.
A 21-year-old was taken into custody while authorities were studying an extremist manifesto purportedly written by the gunman. US media identified him as Patrick Crusius, who is white. He surrendered to police about a block away from the Walmart.
The "manifesto" purportedly written by Crusius that was circulated online includes passages railing against the "Hispanic invasion" of Texas and the author makes clear that he expected to be killed during his attack.