A city is on lockdown after a gunman reportedly stormed a busy office building and started shooting.

The suspect is said to have rushed into an office block in the US city of Dallas, Texas, and started shooting. At least one person is believed to have sustained gunshot wounds, although their condition is not clear at this stage. The entire area was reportedly evacuated and authorities blocked off nearby streets.

A SWAT team immediately raced to the scene as a mass evacuation of the area was carried out. Local reports state the shooter entered the building near Interstate 635 and Schroeder Road at 10.10am (4.10pm UK time). The suspect then apparently gunned down his boss before turning the gun on himself. The extent of both of their injuries is not clear at this point.