Siemens executives defended their $7.6 billion deal to buy U.S. oilfield equipment firm Dresser-Rand, saying oil demand would grow long-term and synergies could increase.

"There's no reason to think there's a different valuation now than at the time we agreed it," Chief Financial Officer Ralf Thomas told journalists, responding to concerns about investments in shale exploration falling with the oil price.

Siemens earlier reported that profits from its industrial units fell 4 percent last quarter, ahead of an annual shareholder meeting expected to be stormy as investors challenge the Dresser-Rand acquisition.