(AP) — An increasing number of American citizens have been apprehended as they have tried to smuggle illegal drugs into the U.S. since the start of the coronavirus pandemic. For more than a year, the closure of the U.S.-Mexico border to nonessential traffic has limited the number of foreign citizens entering the U.S. by land. The rules have been extended until at least June 21. But Mexican authorities have allowed most U.S. citizens to walk or drive south across the border with relative ease. Law enforcement officials and drug trafficking experts say the border rules and their lopsided enforcement are driving the rise in U.S. citizens involved in borderland drug busts.