Clashes sparked by suspected cartel gunmen in a northern Mexican town killed 20 people this weekend, putting more pressure on Mexico’s president to curb gang violence after the United States vowed to label the gangs as terrorists.

President Andres Manuel Lopez Obrador, mindful of efforts by US President Donald Trump to designate Mexican drug gangs as terrorist groups, repeated on Sunday that he would not accept any intervention from abroad, while doubling down on his strategy of trying to contain the cartels.