In Iraq, a Polish soldier was killed and three others injured by a remote-controlled mine which exploded overnight, Polish radio Zet reported on Thursday. Defense Ministry spokeswoman Agnieszka Kucharska confirmed the casualties but said she had no further details on the incident, including exactly when it happened. "One is dead and three are wounded," Kucharska said. In the meantime, fighting between Iraqi fighters and American forces west of Baghdad has killed two U.S. Marines, the military said in a statement Thursday. The two Marines died in clashes Wednesday in Anbar province, the statement said. The U.S. military had initially said two coalition troops were killed during heavy fighting Wednesday in the Anbar city of Ramadi, but it had declined to reveal their nationalities. Multiple U.S. military camps in Ramadi came under mortar attack Wednesday and two U.S. helicopters made emergency landings after coming attack from small arms before returning to their base, the military said. **Iraq national conference postponed*** The postponement of the Iraqi national conference scheduled for 31 July, comes as no surprise given the controversy surrounding it. The event's organisers had billed it as Iraq's first effort at democracy-building. But others were less receptive. One of their main criticisms has been that the conference would not be representative. Jamal Benomar, a United Nations representative sent to help coordinate the event, says not enough is being done to make the gathering as inclusive as possible, particularly given the country's lack of experience with democracy. The conference, described by some as a crucial step in Iraq's political transition in the run-up to elections in January, is now expected to be held in mid-August. It is expected to draw around 1000 delegates from around the country. The Association of Muslim Scholars, Iraq's highest Sunni religious authority, has said it will not participate, and another key Sunni party, the Iraqi Islamic Party, has also decided to keep away, calling the conference "fixed". **PHOTO CAPTION*** Children gather bomb fragments from a crater left in the courtyard of a house in the southwestern part of Fallujah, after US warplanes hit Iraqi house. (AFP)