* Aug sales up 0.1 pct, weakest month in at least 2.5 yrs
* VW reaffirms goal to increase full-year sales
* Six main car brands may post almost 11 mln 2018 sales
BERLIN, Sept 13 (Reuters) - Volkswagen's global car sales were almost flat in August and the German automaker pointed to difficult conditions in Europe, one of its core markets.
Global deliveries rose just 0.1 percent last month to 720,400 cars, which compared with a rise of 3.2 percent in July. This makes August the weakest sales month in at least 2.5 years for the German company, which also includes luxury division Audi and sports-car maker Porsche.
The slowdown partly reflected the impact of a big hailstorm in July, which damaged up to 17,000 new cars at VW's Wolfsburg base. Deliveries had to be delayed while the cars were repaired.
Global sales in the eight months to August were up 4.5 percent to 6.17 million. In Europe, sales dropped 3.3 percent in the year-to-date period.
"Despite difficult conditions we still expect 2013 deliveries to exceed year-ago levels," sales chief Christian Klingler said.
Europe's largest auto manufacturer, which has a goal to overtake Toyota and General Motors to snatch the world's sales crown no later than 2018, aims to boost sales to 9.5 million cars this year, up from 9.3 million in 2012.
Global deliveries of the group's six car divisions - VW's namesake brand, Skoda, Seat, Audi, Porsche and Bentley - may grow to almost 11 million autos by 2018, finance chief Hans Dieter Poetsch said in a presentation to investors at the Frankfurt motor show on Sept. 9.
VW has so far been saying that group deliveries, also including truckmakers MAN and Scania as well as commercial vehicles and ultra-luxury brands Lamborghini and Bugatti, might exceed 10 million by 2018.