As it happened: US school shooting

Key Points

• Twenty children and six adults have been killed in a shooting attack at a primary school in the US state of Connecticut.
• US media identified the gunman, who was also killed, as Adam Lanza - not his brother Ryan as initially reported.
• There is also a dead adult - believed to be the gunman's mother - at a second crime scene near the school.
• President Obama says 'our hearts are broken today' as he pays tribute to the victims