Theodore Scardino, one of the firefighters "significantly wounded" in the shooting in Webster, New York, has spoken since treatment, say Strong Memorial Hospital staff.
Scardino is able to breathe on his own, but staff said both he and Joseph Hofsetter were "at risk" and being monitored for bleeding.
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More than 1.85 million people have called for the US president's visit to be watered down to avoid causing "embarrassment" to the Queen.
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