The death toll in weekend mass shooting in El Paso, U.S. state of Texas, has risen to 22 after two people died at a hospital, El Paso police and medical officials said Monday.

The Del Sol Medical Center in El Paso confirmed the deaths during a news conference Monday. One victim died on Sunday night, and another died on Monday morning.

According to officials with the Del Sol Medical Center, there are five patients in stable condition and one in critical condition at the hospital. One patient has been transferred.

Three Mexican nationals are among the dead and another six among the injured, Mexican officials said late Saturday. No first responders were among those killed or injured.

U.S. President Donald Trump said on Monday morning the shooter's manifesto was "consumed with racist hate."

He called for mental health gun control reforms, the death penalty for those who commit mass murder and more bi-partisan cooperation over gun laws.

On Sunday, Trump issued a proclamation, ordering that all American flags at military installations, federal facilities, and the White House be flown at half-staff until sunset on Aug. 8.

On Monday, three service dogs from Texas city of San Antonio arrived in El Paso to patients and families of shooting victims.

Their handlers say the dogs from the Methodist Healthcare System are specially trained to help people experiencing grief, stress and trauma, local media reported.

The attack in the border city of El Paso in Texas happened on Aug. 3 at a Walmart mall. More than 20 people were also injured in the attack with several in serious condition. The victims' identities have not been released. A 21-year-old white male has been arrested.