BRUSSELS, June 29 (Reuters) - EU antitrust regulators will decide by Aug. 2 whether to clear Facebook"s (FB.O) acquisition of U.S. customer service startup Kustomer, a filing on the European Commission website showed. The world"s largest social network announced the deal in November to help it scale up its instant messaging app WhatsApp, which has reported a jump in usage during the COVID-19 pandemic. The EU competition regulator wants to vet more tech, pharma and biotech startup deals for signs of so-called killer acquisitions where tech giants buy nascent rivals to close them down. Austria had asked the Commission to take over its review. The Commission can clear the deal with or without conditions or it can open a four-month investigation if it has serious concerns.