Candy maker Mars' takeover of Pringles maker Kellanova was cleared by U.S. antitrust regulators on Wednesday, but their EU counterparts opened a full-scale investigation into the $36 billion deal, saying it could lead to price hikes.

Mars Inc. and Kellanova are expecting a positive resolution of a review of the companies’ proposed deal by European Union regulators, according to a filing from Kellanova on Wednesday.

European Commission officials set an Oct. 31 deadline to make a decision on the probe.