text:  You're listening to the latest world news from the BBC. Ukraine's military says its commander-in-chief, General Oleksandr Sirski, has ordered an investigation into why one of his brigades has been suffering high levels of casualties. It follows allegations from a paramedic who'd served in the 59th Separate Motorised Infantry Brigade. The paramedic had accused its commander of negligence. He's yet to respond to the allegations.