BAGHDAD (AFP) - Seven American soldiers were killed on Thursday when their transport helicopter crashed in southern Iraq, the deadliest such incident in the country in more than a year, the US military said. The CH-47 Chinook crashed about 100 kilometres west of the main southern port city of Basra as it was flying as part of four-aircraft convoy flying from Kuwait to the northern city of Balad, it said. "The seven soldiers were the only ones on board the Chinook at the time of the crash," the US military said in a statement. The crash comes just two days after US General Raymond Odierno took over as the new commander of US-led forces in Iraq from General David Petraeus. British military spokesman Major Paul Smyth said a British quick reaction force was dispatched from Basra and a British road convoy in the vicinity was diverted to the scene of the crash. He said both British and US personnel were at the scene. The US military said the incident was under investigation. "However enemy activity is not suspected," it added. "It is a tough day for the coalition and we are deeply saddened by the loss of our soldiers," said Colonel Bill Buckner, a spokesman for the US military. The crash was the worst since August 2007 when a US Blackhawk transport chopper crashed in northern Iraq, killing 14 US military personnel.