Just appeared on the UK news:
Under the sub-headline 'Gunmen have killed seven people and wounded 12 others in a rampage...' One gunman was in custody, but another remained on the loose on the sprawling base in Kileen, Texas, about 60 miles north-east of Austin. The base was on lockdown after it emerged that a second shooter was believed to be armed with a high-powered sniper rifle, according to a report on MSNBC television. Two nearby school districts were also reportedly on lockdown. John Carter, a local congressman, confirmed on MSNBC there had been a shooting at the base, saying the gunfire had erupted during a graduation ceremony.

BBC has a slightly different report:http://news.bbc.co.uk/1/hi/world/americas/8345713.stm