MEXICO CITY --- Greater quantities of synthetic opioid fentanyl directly enter the United States and Canada than Mexico, Mexico's president said Thursday, pushing back against U.S. criticism of his record on cracking down on trafficking in the lethal drug. A powerful painkiller, fentanyl has been blamed for fueling a surge in U.S. drug overdoses, and some Republican lawmakers have urged Washington to authorize the use of military force in Mexico to bring the country's drug gangs to heel. Last month, Anne Milgram, head of the U.S. Drug Enforcement Administration (DEA) told a U.S. congressional hearing on drug trafficking that Mexico's Sinaloa Cartel and rival Jalisco New Generat...Keep on reading: Mexican president says more fentanyl enters the U.S. and Canada than Mexico