BRUSSELS (Reuters) - The European Commission said on Tuesday it had launched an in-depth investigation into oilfield services provider Halliburton's (>> Halliburton Company) planned purchase of its smaller rival Baker Hughes (>> Baker Hughes Incorporated).

"The commission has to look closely at this proposed takeover to make sure that it would not reduce choice or push up prices for oil and gas exploration and production services in the EU," Commissioner Margrethe Vestager said in a statement.

Halliburton offered in November 2014 to buy Baker Hughes for about $35 billion in cash and stock, creating an oilfield services behemoth to take on market leader Schlumberger NV (>> Schlumberger Limited.) as falling oil prices force customers to curb spending.

The No. 2 and No. 3 players in the services industry said the decision is a normal step in the commission's review process.

Halliburton said it expects to offer a substantial remedies package that will address any substantive competition concerns.

The two companies said last month that U.S. antitrust officials were not satisfied with proposed concessions.

Halliburton's shares were down 2.15 percent at $30.88 in afternoon trading, while Baker Hughes was down 2 percent at $40.67.

(Reporting By Philip Blenkinsop and Sneha Banerjee in Bengaluru; Editing by Alissa de Carbonnel and Don Sebastian)