People bring flowers to a memorial site for mass shooting victims in El Paso of Texas, the United States, on Aug. 4, 2019. The US federal government is treating a mass shooting in the US state of Texas on Saturday as a domestic terrorism case, the US attorney for the Western District of Texas said Sunday. The attack in the border city of El Paso in Texas left 20 people dead and 26 wounded. A 21-year-old white male has been arrested. (Xinhua/Liu Liwei)

A temporary memorial site for mass shooting victims is seen near the Walmart shopping mall area in El Paso of Texas, the United States, on Aug. 4, 2019. The US federal government is treating a mass shooting in the US state of Texas on Saturday as a domestic terrorism case, the US attorney for the Western District of Texas said Sunday. The attack in the border city of El Paso in Texas left 20 people dead and 26 wounded. A 21-year-old white male has been arrested. (Xinhua/Liu Liwei)

A man lays flowers at a memorial site for mass shooting victims in El Paso of Texas, the United States, on Aug. 4, 2019. The US federal government is treating a mass shooting in the US state of Texas on Saturday as a domestic terrorism case, the US attorney for the Western District of Texas said Sunday. The attack in the border city of El Paso in Texas left 20 people dead and 26 wounded. A 21-year-old white male has been arrested. (Xinhua/Liu Liwei)

A man mourns for mass shooting victims at a temporary memorial site in El Paso of Texas, the United States, on Aug. 4, 2019. The US federal government is treating a mass shooting in the US state of Texas on Saturday as a domestic terrorism case, the US attorney for the Western District of Texas said Sunday. The attack in the border city of El Paso in Texas left 20 people dead and 26 wounded. A 21-year-old white male has been arrested. (Xinhua/Liu Liwei)