WARSAW, Dec 8 (Reuters) - A four-year-old Iraqi migrant girl went missing in an icy forest after being separated from her parents in a scuffle with Polish border guards, humanitarian groups said as they pressed for access to the border region to help find the child. Poland has sealed off the region along its frontier with Belarus to outsiders as it has sought to keep out thousands of people from the Middle East and Africa who travelled to Belarus in the hope of crossing into European Union territory. The EU accuses Belarus of flying them into the country and then pushing them to cross into Poland and - to a lesser extent - Lithuania and Latvia in retaliation for sanctions imposed on Minsk over human rights abuses. Humanitarian groups reported on Wednesday that the Iraqi girl, called Eileen, was separated from her parents after they breached the border into Poland on Monday night. They said the parents handed their daughter to another adult migrant when Polish border guards approached and pushed them back into Belarus, and the girl was last seen with the person accompanying her near the Polish frontier village of Nowy Dwor. "This girl is probably either already dead or will die very soon. The most dramatic thing is that if it was a Polish child, the whole country would be looking for her," Kasia Kosciesza from the Families without Borders charity group said. "The search should have started as soon as they knew of the situation...Chances are diminishing, night is setting in again and temperatures will start falling, so if we want to rescue her, it needs to happen immediately." Border Guard spokeswoman Anna Michalska said servicemen started searching for the girl as soon as they received information she was missing around midday on Tuesday. "Extra patrols were directed to the area where the girl was supposed to be. We also searched from the air using helicopters, but we found no one," Michalska said. Campaigners said the authorities" efforts were inadequate. Under new rules introduced after a state of emergency in the migrant crisis expired last week, activists who are not resident in the border area cannot enter to help with any search. International organisations have accused Poland"s right-wing nationalist government of breaching humanitarian standards in forcing some migrants back into Belarus, a charge Warsaw denies.