The European Union's executive, the Commission, has objected to United Parcel Service's proposed $6.75 billion takeover of TNT Express NV, the companies say. They say the watchdog argues that the deal as it stands would have a negative effect on the market for express delivery of small packages in Europe.

The companies said in a joint statement Friday they would respond to the objections within several weeks — presumably offering concessions — and still expect approval for the takeover in early 2013.

The companies said they believe the European express delivery market is competitive, with "multiple players who offer similar services," while customers would benefit from the companies' combined product offerings. UPS is the biggest express delivery company globally, while TNT Express is the second-largest European express deliverer, after Deutsche Post's DHL.