Two more victims of the mass shooting  at a Walmart store in El Paso, Texas have died of their wounds on Monday. The two deaths raises the death toll in the massacre to 22.

The latest fatalities bring to 31, the number of people who were killed during the weekend in mass shootings in El Paso and Dayton, Ohio.

Prime suspect, 21-year-old Patrick Crusius has been charged with a single count of capital murder in the El Paso case in which eight of the persons killed were confirmed to be Mexican citizens.

US authorities cited a lengthy anti-immigrant manifesto, apparently posted online by the suspect before the Saturday morning shooting in the heavily Hispanic border city which they said was evidence that the bloodshed was racially motivated.

The four-page statement uploaded to 8chan, a largely uninhibited online message board often used by extremists called the Walmart attack a response to the Hispanic invasion of Texas, expressing support for a gunman who killed 51 people at two mosques in Christchurch, New Zealand few months ago.

The El Paso killings also prompted 8chan founder, Frederick Brennan to call for the site to be shut down. The social media site is now being run from the Philippines by a US army veteran.