Australia's prime minister on Thursday called the deaths of five of the country's soldiers in Afghanistan - three killed by an Afghan army colleague - Australia's worst day in the more than decade-long war, according to AP. The Australians were killed in two separate incidents just hours apart late Wednesday and early Thursday. The first incident took place at a base in Uruzgan province, when a man in an Afghan army uniform opened fire on Australian soldiers, killing three and wounding two, according to Air Marshal Mark Binskin, vice chief of the Australian Defense Force. Hours later, two Australian soldiers died and a crew member was wounded when their helicopter rolled over while landing in Helmand province. "In a war of so many losses, this is our single worst day in Afghanistan," Prime Minister Julia Gillard said. "Indeed, I believe this is the most losses in combat since the days of the Vietnam War and the Battle of Long Tan. This is news so truly shocking that it's going to feel for many Australians like a physical blow." The Australians were relaxing at the base when the assailant began shooting at close range with an automatic weapon, Binskin said. Soldiers at the base returned fire, but the shooter scaled a fence and escaped. The Australians tried to revive their comrades, but the wounds proved fatal, he said. One of the wounded soldiers sustained a serious gunshot wound and was evacuated to another base for further treatment. He is in satisfactory condition. The other was treated at the scene. The Afghan soldier accused of the shooting is named Hekmatullah, and was working as a night guard at the Afghan army base where the international troops had stopped to spend the night, Afghan officials said. Hekmatullah fired at the Australians as they entered the base in Uruzgan province's Chora district, said Abdulhameed Hameed, an Afghan army commander in the south. Australian and Afghan soldiers were hunting for the killer Thursday, Binskin said. He would not release further details of the attack, and said the shooter's motive was unknown.