AMSTERDAM (Reuters) - Authorities in the Netherlands tried on Tuesday to defuse a threat by Moscow to close Russian air space to Dutch planes in a dispute over landing slots at Amsterdam s Schiphol airport.  The Dutch Airline Pilots Association said Russia has indicated it will enforce the ban from Saturday. It would mainly hurt Air France subsidiary KLM, the former Dutch flag carrier and the only Dutch airline that flies over Russia. The dispute centers on a reduction from 23 to 13 in the number of slots available to Russian freight carrier AirBridgeCargo at Europe s third-busiest airport following Schiphol s half-yearly reallocation.on Oct. 28. The Dutch transport ministry is  in talks with several parties over the availability of slots for freight traffic at Schiphol,  said spokesman Roel Vincken, who declined to comment further for fear of negatively impacting the talks. A spokesman for the Russian transport ministry said KLM and AirBridgeCargo were in talks about KLM giving up some of its slots as part of a possible compromise. Russian-Dutch relations have been tense since the 2014 downing of Malaysia passenger flight MH17 over eastern Ukraine, which killed 298 people, most of them Dutch.   AirBridgeCargo s Dutch chief Henk-Jan van Keulen said in a telephone interview that his company had been forced to reroute almost half of its traffic through Liege, Belgium, using trucks, because of the reallocation of slots at Schiphol. Van Keulen said financial damages were difficult to estimate, as they are lessened by lower fees at Liege and are being partly borne by the various freight-forwarding companies it works with. Spokesman Joost van Doesburg said the Dutch Airline Pilots Association had received a request from KLM to add an extra pilot to all flights traveling to Asia, as they will have to re-route beginning on Saturday.  If Russia follows through on the ban, hours of travel time will be added to Asian flights.   It s only a threat but you have to prepare,  Van Doesburg said.  Russia does this sometimes when it feels countries aren t giving appropriate attention to a complaint.      De Telegraaf newspaper reported that around 15 percent of KLM s flights would be affected. A KLM spokeswoman said the airline would respond later. Airport Coordination Netherlands, the organization which allocates slots at Schiphol, said AirBridgeCargo s slots had been cut for failure to fully utilize its existing slots, according to European rules, and it did not have the power to grant any additional slots because of a cap imposed at the airport. 