Iraq's government signed deals for only three of 12 oil and natural gas exploration sites offered in a two-day energy auction that ended Thursday, reflecting reluctance of foreign bidders to risk money in unexplored areas.

The auction was Iraq's fourth since 2009 and was meant to attract foreign investment in the country's crucial energy sector, particularly natural gas exploration. In previous rounds, bidders competed for known oil and gas fields.

The lukewarm response was also blamed on tough contract terms set by the Iraqi government. Companies are paid a flat fee in so-called service contracts, rather than receiving a share of the oil and gas they find.

Oil Ministry spokesman Assem Jihad said the government is not disheartened. "We do not consider three successful bids as a disappointing matter, taking into consideration that foreign companies in general do not like to take risks on unexplored areas," he said.