The blasts Monday in stores in the western Belgian city of Ghent, Lille in northern France and Eindhoven in The Netherlands were caused by "small fireworks devices," Ikea spokeswoman Charlotte Lindgren told AFP.
Belgian authorities said Tuesday booby-trapped alarm clocks detonated by remote control had exploded in the Ghent store, and that the circumstances were similar in Eindhoven and Lille.
"We had not received any threats against Ikea at all," Lindgren said, stressing the blasts had left "a co-worker and a security person (suffering) from ear pains. Otherwise there are no injuries."
Lindgren said dogs had searched through Ikea stores overnight, and "all the stores will or have opened as usual this morning, all of them."
She refused to comment further on what security measures were being taken.