Oil-and-gas company DNO said the board of Genel Energy has rebuffed its 202 million-pound ($271.8 million) takeover proposal.

Norwegian-listed DNO proposed two deal structures. Under the first proposal, Genel Energy shareholders would receive 69 pence in cash for each Genel share. This represents a 38% premium to the stock's closing price on Thursday.

Under the second proposal, Genel shareholders could choose to receive a combination of cash and newly issued DNO shares equivalent in value to the cash offer.

DNO is active in the Middle East and the North Sea, while Genel Energy drills for oil in the Kurdistan region of Iraq, and has exploration assets in Oman and Somaliland.

Genel said it evaluated the possible offer, but rejected it as the proposal undervalues the company. It advised shareholders not to take any action.

Genel is in the process of buying Capricorn Energy for $360 million. The deal remains conditional upon shareholder approval at meetings called for Aug. 18.

DNO said Genel's board rejected the approach on Aug. 4 but that it remains willing to engage with the company on the proposal.

Under U.K. takeover rules, DNO has until Sept. 4 to announce a firm intention to make an offer for Genel or walk away.