In the wake of the military strikes on Afghanistan over the Columbus Day holiday weekend, federal agencies went on heightened alert as administration officials warned that retaliatory terrorist attacks in the United States were possible. In anticipation of further terrorist strikes against Americans, federal officials stepped up security at federal facilities, ports and airports; law enforcement agencies were put on the highest alert; and the State Department warned Americans traveling overseas that they could be targets of anti-American actions. Domestic efforts to shore up security against terrorism will be led by former Pennsylvania Gov. Tom Ridge, who on Monday was sworn in as director of the new White House Office of Homeland Security. While the scope of Ridge's authority is still being worked out, he will coordinate the efforts of more than 40 federal offices that play a role in protecting the nation against terrorism. One of Ridge's most daunting challenges will be to improve control over people and goods entering the United States. Several agencies, including the Immigration and Naturalization Service, the Coast Guard and the Customs Service, are responsible for screening border traffic. All three agencies are poorly equipped and under-staffed for the job. For example, the INS has fewer than 350 Border Patrol agents assigned to monitor the 4,000-mile border with Canada; the Customs Service is able to inspect fewer than 2 percent of the commercial shipments that enter the United States; and the multi-mission Coast Guard is operating with one of the oldest fleets in the world. Ridge faces a "huge challenge," according to retired Gen. Barry McCaffrey, the Clinton administration drug czar. There is currently no central organizing authority on the border, McCaffrey said. In trying to reduce the flow of drugs into the United States, McCaffrey encountered many of the bureaucratic problems Ridge will need to solve if he is to be successful in reducing U.S. vulnerability to terrorism.