Spanish oil major Repsol Monday announced it had acquired a 70-percent stake in several exploration blocks in Alaska, where it plans to invest around 550 million euros.

"This deal forms part of our strategy to incorporate new and high quality exploration sites into our portfolio," Repsol chairman Antonio Brufau said in a statement released by the group.

It is also "part of our strategy to balance our exploration portfolio with low risk assets through onshore opportunities in a stable environment," he said.

Repsol said last month said it had halved its oil production in Libya because of the escalating anti-government protests in the country.

The group sealed the Alaska agreement with two Denver-based companies, "70 & 148, LLC (a subsidiary of Armstrong Oil and Gas Inc.)" and "GMT Exploration LLC", with whom it will jointly operate the blocks.

It said the blocks are close to large oil-producing fields and stretch over some 2,000 square kilometres (770 square miles) in Alaksa's North Slope, a region that is "particularly rich in oil."

The exploration of the first well is planned for next winter.

It did not indicate the amount of the deal but said it plans to invest at least $768 million (548 million euros) in acquisitions and exploration in the region in the coming years.