* Core operating profit back at pre-pandemic levels * Organic sales growth slowed in North America * Airport security recovers after travel slump (Adds detail, analyst comment, updates shares) STOCKHOLM, Oct 29 (Reuters) - Core profit at security services group Securitas was back at pre-pandemic levels in the third quarter as even its hard-hit airports business shook off some of the effects of previous restrictions. The Swedish group said on Friday that so far this year it had raised prices on a par with wages - its single biggest cost. “Labour shortage and wage pressure remain a challenge. Maintaining the price and wage balance is a key priority throughout the Group going into 2022,” it said. However, Securitas shares dropped around 4% as analysts said quarterly organic sales growth of 4% was lower than expected amid slower growth at the North American security services unit. Securitas, whose services include guards, alarm surveillance and airport security, said the division had been held back by a lower level of pandemic-related sales than a year earlier. The company, whose biggest competitor is privately held U.S. group Allied Universal after it bought G4S this year, said it made a third-quarter operating profit before amortisation of 1.61 billion Swedish crowns ($189 million). That was up from 1.33 billion crowns a year earlier and also slightly above the 1.57 billion made in the third quarter of 2019, before the pandemic. “The gradual business recovery from the corona pandemic continued in the third quarter, with commercial activity and sales momentum picking up in all of our business segments, including airport security,” Chief Executive Magnus Ahlqvist said in a statement. $1 = 8.5221 Swedish crowns Reporting by Anna Ringstrom Editing by Niklas Pollard and Mark Potter