Prime Minister Hun Sen has announced his intention to run for another term at the 2018 election and said he will replace his ailing one-time rival Chea Sim as ruling party president when the 83-year-old dies.

Speaking at the opening of a palm oil processing plant owned by ruling Cambodian People’s Party senator and longtime party patron Mong Reththy, Hun Sen, Asia’s longest-serving leader, also dismissed rumours that he was preparing the way for a transition of power.

“Make no mistake, today I present a clear message because of persisting whispers about how Hun Sen may not stand as a candidate for prime minister,” he said. “The [CPP] candidate for the premiership will remain Hun Sen for the [next government] and forever. Nobody will replace Hun Sen, and the CPP will win again [in 2018].”

The 63-year-old prime minister, who has of late forged a truce with longtime foe and opposition Cambodia National Rescue Party president Sam Rainsy, also announced at the factory opening that he would assume the position of CPP president in the event of the death of the incumbent, Chea Sim.

“We wish Samdech Chea Sim to be in good health and live a long life even if he cannot work, and he will be president of the CPP and Senate [as long as he lives].”

Sim once led a powerful faction within the CPP that was often at odds with Hun Sen’s, but party insiders now speak of the ailing party president’s role as little more than symbolic.

“The CPP have been living together for 36 years in power. The CPP is united,” Hun Sen said. “There’s no fighting in the CPP to get power, and no need to protest to expel one another.”

In 2004, Sim was escorted out of the country after refusing to sign off as acting head of state on constitutional changes that would pave the way for the CPP and Funcinpec to form a coalition government under a deal between Hun Sen and Prince Norodom Ranariddh.

The incident was the first major public display of infighting within the party and a turning point in the power struggle between Hun Sen and Sim, analysts say. Since then, Hun Sen has continued to replace Sim loyalists with his preferred candidates for important positions.

Sim was conspicuously absent from the party’s 63rd anniversary celebrations last June, following years in which age and illness have forced him to take a back seat. At the anniversary event, Hun Sen was publicly referred to as “acting CPP president” for the first time.

Say Chhum, CPP secretary general, who is seen by many to occupy the middle ground between the two factions, will become the Senate leader when Sim dies, Hun Sen said.

He went on to poke fun at the royalist Funcinpec party, saying that party leader Ranariddh used to pry him for information on possible rifts within the CPP during meetings at the Royal Palace. “But in the end there was a rift within Funcinpec, which split from one into eight while the CPP has remained strong.”

Sok Eysan, a CPP spokesman, said the “rumours” of a Chea Sim-Hun Sen divide in the party had persisted since the 1993 election, and blamed rival parties for spreading misinformation.

“There are exchanges of ideas, but that doesn’t mean we have a problem. This rumour was just based on the ambitions of our opponent political parties, which wanted to weaken the CPP,” he said.

Sim’s health remains stable, though he is housebound, he added.

Independent political analyst Chea Vannath said the announcement that Hun Sen would assume leadership of the party after Sim died “had been [brewing] for quite a long time”.

“And with the succession, they were not in a rush to announce a decision. Maybe they planned that a long, long time ago within the party. Perhaps it’s agreeable among different players in the party.”

ADDITIONAL REPORTING BY DANIEL PYE