A military plane crashed in a forested area in northwestern Poland, killing 20 people, the prime minister said early Thursday. The officers had been attending a flight safety conference in Warsaw. Prime Minister Donald Tusk said the plane crash, which occurred as it was about to land Wednesday evening. The 20 victims included a brigadier general and four crew members, he said. "Soldiers, husbands, and fathers have died, and that is the most tragic result of this catastrophe," said Tusk, who had rushed to the site of the accident. He called it a "huge loss for the Polish air force."