UPDATE 1-EU opens investigation of StatoilHydro-Conoco deal

(Adds StatoilHydro comments)

BRUSSELS, May 14 (Reuters) - The European Commission ordered an in-depth investigation on Wednesday into plans by Norway's StatoilHydro (STL.OL: Quote, Profile, Research, Stock Buzz) to buy 274 automated petrol stations in Norway, Sweden and Denmark from ConocoPhillips (COP.N: Quote, Profile, Research, Stock Buzz).

The Commission said the two companies overlap in the market for retail motor fuel supply and that price competition might be affected by the deal.

"The Commission's initial investigation showed that this overlap might create competitive concerns in Sweden and Norway, where Jet may exert competitive pressure on Statoil leading to a significant impact on Statoil's retail prices," the Commission said in a statement.

The Commission's investigation into the deal, which covers Jet-branded automated stations -- 39 in Norway, 72 in Denmark and 163 in Sweden -- will last until Sept. 18.

Competition Commissioner Neelie Kroes said rising oil prices make it important to have competition at the retail level for gasoline stations.

"It appears that Jet has until now kept a downward price pressure on Statoil and that pressure may be permanently lost after the merger. We now need to find out if a more detailed investigation confirms this initial view," she said.

StatoilHydro, mainly focused on producing oil and gas offshore Norway, seeks to become the leading transport fuel company in Scandinavia in part by strengthening its retail operations.

"When it comes to this type of business transaction it is not unusual to get to this (EU probe) phase," StatoilHydro's chief spokesman Ola Morten Aanestad said. "We would have wished for a faster process."