WASHINGTON - US forces in Afghanistan can expect high casualties as more forces roll in to help prop up the government and end the insurgency, US defence officials were quoted as saying in media reports. President Barack Obama called for another 30,000 troops for Afghanistan in December when he unveiled his revised war strategy. The last of those troops should be on the ground by the end of August. A top US military official speaking on background at the Pentagon said US forces should be braced for a hard fight, the Defence Department said. It will be a tough fall, the senior official warned. But what were gaining is, were clearing these areas that never have been cleared. July was the deadliest month for US combat forces in Afghanistan with 65 reported fatalities. More than 1,000 US soldiers were killed during combat operations in Afghanistan since the war began in 2001. US, Afghan and international forces are focusing their fight in Taliban heartland in southern Afghanistan in order to install a friendly government as the country prepares for elections next month. There are more than 2,500 candidates, including 400 women, scheduled to compete for the 249 seats in the lower house of Parliament, or Wolesi Jirga. Staffan de Mistura, the UN special envoy to Afghanistan, said security could be the real spoiler in the September elections.