A 15-year-old girl remains in a "critical"condition after being shot at a Arapahoe High School in Denver, Arapahoe County Sheriff Grayson Robinson told a news conference.
Two other students injured in the attack have been released from hospital.
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Uplifting messages greeted commuters on the London Underground a day after the terror attack in Westminster.
Faith leaders from across London say religious communities will "stand together" in the wake of the Westminster terror attack.
Pc Keith Palmer was among the three people killed yesterday in the Westminster terror attack.