Turkish President Recep Tayyip Erdogan dug in his heels Monday in what appears to be a widening rift with his own government over the Kurdish peace process.

Turkish President Recep Tayyip Erdogan dug in his heels Monday in what appears to be a widening rift with his own government over the Kurdish peace process.

In a sign of simmering tensions at the top, Erdogan's longtime deputy Bulent Arinc told the president over the weekend to stop interfering and making "emotional" statements about efforts to end the three decades-long insurgency in the southeast.

But Erdogan, seen as all-powerful since being elected head of state last year after 11 years as prime minister, hit back Monday in a televised speech: "The peace process began and reached the current stage under my responsibility. It is both my right and duty to voice my opinion," he said.

Ankara mayor Melik Gokcek, an Erdogan loyalist, later called on Arinc to resign, accusing him of trying to undermine the ruling Justice and Development Party (AKP) -- which he co-founded with Erdogan -- from within.

In a series of tweets he accused the Deputy Prime Minister of being a tool of the "parallel state", a reference to the Gulen movement.

"I always wondered... how they will strike at us," Gokcek wrote. "I must confess I wasn't expecting such a blow... they wanted to strike at us from within."