Activist investor Carl Icahn on Tuesday urged Caesars Entertainment Corp. to sell itself, after disclosing a 9.78 percent stake in the U.S. casino operator.

"Board should conduct a strategic process to comprehensively assess the best path forward for Caesars and believe that shareholder value might be best served, and enhanced, by selling the company," Icahn said in a regulatory filing.

Icahn's push for a sale of the company comes after Caesars rejected a merger approach last year by Tilman Fertitta, the billionaire owner of Golden Nugget Casinos.

Caesars, whose casinos include the Harrah's and Horseshoe brands, emerged from bankruptcy in 2017 after failing to cope with some $25 billion in debt.

Its long-term debt stood at about $8.81 billion as of Sept. 30, 2018.

Icahn said he was seeking board representation at Caesars, including, if necessary, nominating a slate of directors at the company's 2019 annual meeting.

"We believe that our brand of activism is well-suited to the situation at Caesars, which requires new thought, new leadership and new strategies," Icahn said.

Caesars shares rose nearly 5 percent to $9.59. Up to Friday's close, the stock had risen 14.5 percent since Jan. 11, when reports of Icahn building a stake in the company emerged.