Apparent terrorist attack in London subway

NBC - Police in London, England say a reported explosion on the subway Friday morning was a terrorist incident.

A commuter whose train had just left the station in southwest London says there was panic after the apparent explosion.

The witness says he saw several people injures, apparently trampled as they fled.

The London ambulance service said multiple crews had been dispatched.

The incident happened during rush hour when the underground system is crowded.