Police bolstered security in subways and trains Wednesday after the government warned that al-Qaida suicide bombers were contemplating an attack on New York's mass-transit systems during the holiday season. An internal memo obtained by The Associated Press says the FBI has received a "plausible but unsubstantiated" report that al-Qaida terrorists in late September may have discussed attacking the subway system.

The internal bulletin says al-Qaida terrorists "in late September may have discussed targeting transit systems in...