| Nb: site continues to update as reports come in. |
6:29 pm ET: Boston hospitals report "multiple amputations" among those injured at Boston Marathon.
6:13 pm ET: "We will find out who did this and we will hold them accountable," says President Obama.
6:12 pm ET: We do not know who did this or why... But make no mistake. We will get to the bottom of this," says President Obama.
6:11 pm ET: "On days like this there are no Republicans and Democrats," says President Obama.
6:10 pm ET: President Obama is now addressing the nation.
6:04 pm ET: Sen. Dianne Feinstein, D- Calif., chairman of the Senate Intelligence Committee, tells ABC News: "It is a terrorist incident. ... It could be foreign, it could be homegrown." She said the attack had the "hallmarks" of a terror attack.
6:02 pm ET: ATF agents have descended on Brigham and Women's hospital where they're questioning one potential person of interest.
5:56 pm ET: At least 86 people have been taken to area hospitals, according to a tally by ABC News.
5:48 pm ET: FAA lifts restrictions on air travel over Boston. Logan Airport has been reopened.