we must take these threats ce. st take these threats the public is likely to see and may be somewhat inconvenienced by vehicle checkpoints at various locations throe rorter: u.s. officials have been bracing for just such a plot after disdocu in binin laden s pakistan hideo in which he e lled for a strike against the u.s. on the tenth anniversary ofr 11 in zawahiri s most recent video last month, he called on his followers to focus on the u.s. track her down, he said,d,nd make an example out of her. the united states has been looking very intently the last few weeks for any sign of this attack coming because it made sense to u.s. intelligence that al qaeda would try it. reporter: police in new york say they plan a full show of force on friday morning with random vehicle checks, bag checks, bomb dogs everywhere, and preplanned exercises involving police and heavily armed national guard personnel at major transportation hubs. brian ross, abc news, new york. taking this seriously