Before police arrived, one of the suspected killers, covered in blood and holding knives, spoke to an onlooker who recorded the scene.
Two suspects were later shot and wounded by the police, officials said, and were in separate hospitals under police guard. London's Metropolitan Police confirmed to NBC News that the two men have now been arrested.
British Prime Minister David Cameron cut his trip to Paris short, quickly returning to chair an emergency national security meeting in London. “There are strong indications that it is a terrorist incident,” he said. The killing was “an appalling murder” and “absolutely sickening.”
Clearly concerned about anger or retaliation, the Muslim Council included in its statement a “Note to Editors” urging them: "Read ‘Remembering the Brave: The Muslim Contribution to Britain’s Armed Forces.'"
Security officials in the U.S. are on alert at British consulates and embassies following Wednesday's attack in broad daylight.
"Based not on information that such facilities have been targeted in New York City but in an abundance of caution, the NYPD has increased coverage of the British consulate, military recruiting stations, and other locations in the city as a result of the fatal attack today on an active serving British soldier near the Royal Artillery Barracks at Woolwich Common in southeast London," said New York Deputy Police Commissioner Paul Browne in a statement.