Turkey's ruling party was on Sunday set to select President Recep Tayyip Erdogan as its chief after a nearly three year break, swiftly pouncing on a key change agreed in the controversial April referendum on expanding his powers.
The special congress of the the ruling Justice and Development Party (AKP) in Ankara was to choose Erdogan -- the only candidate -- to replace Prime Minister Binali Yildirim as party chairman.
Erdogan had rejoined the AKP, which he co-founded, on May 2 after a majority of voters on April 16 approved the changes to create an executive presidency.
Under the old constitution, the head of state had to sever ties with their political party and Erdogan in August 2014 left the AKP and stepped down as chairman after his election as president.
Taking the reins of the party will give Erdogan day-to-day control over its decision making, appointments and strategy as it prepares for elections in 2019.
Thousands of party faithful crammed into the Ankara sports arena gave Erdogan a rock star-like reception as he attended his first major party event since 2014.
The president threw flowers into the crowds while his personal song by the Turkish pop star Ugur Isilak boomed from the speakers.
"We are together again," Erdogan told thousands waiting outside the event in a brief preliminary speech from the top of a bus, noting he was resuming his old job after a 998-day absence.
Rejoining the AKP was the first major change permitted after the referendum, allowing the president to be affiliated with a political party almost immediately.
Erdogan narrowly won with 51.4 percent of the vote but most of the new system, including axing the role of premier, will not come into force until elections on November 3, 2019.
However as leader, Erdogan can decide the party's direction as it prepares for March 2019 local elections and then simultaneous legislative and presidential elections in November that year.
Yildirim, who is staying on as prime minister, will be given a newly-created role of vice chairman, AKP deputy chairman Hayati Yazici said on Saturday.
Erdogan led the party for three terms during his premiership between 2003 and 2014, helping build the AKP into an all-conquering election machine that has yet to be defeated at the ballot box.
The father-of-four affectionately describes the AKP -- the most effective Islamic rooted-political force in the history of modern Turkey -- as his "fifth child".
After becoming a party member again in an emotional grand ceremony in Ankara earlier this month, Erdogan said he had "returned to my home, my passion, my love".
With Erdogan as party leader, all eyes will be on a possible cabinet reshuffle, with Hurriyet daily speculating at the weekend that eight to 10 ministers could be reshuffled.
Once Erdogan is elected by the congress, it will be the first time the president will be both party chairman and head of state since the end of the presidency in 1950 of Ismet Inonu, the successor and right-hand-man of Mustafa Kemal Ataturk, Turkey's modern founder.
Images of Erdogan with slogans such as "iron will, strong Turkey" and "full steam ahead with the founding leader" flooded social media and appeared on street billboards.
A special congress slogan read "a new breakthrough period: democracy, transformation, reform", hinting at a restructuring of the government as well as changes to the party's executive in the coming weeks and months.
Erdogan told party officials "the new period means a new action plan" without giving details, Hurriyet daily reported on Saturday.
According to Aykan Erdemir, senior fellow at the Foundation for Defense of Democracies, becoming chairman would mean Erdogan gains the "formal authority to determine who runs for office from AKP lists".
"This new prerogative will allow him to design both a party apparatus and a parliamentary group composed entirely of loyalists."
Well-connected Hurriyet columnist Abdulkadir Selvi previously said Erdogan would oversee a shake-up of AKP leaders at the local level determined by their success in the referendum.
Turkish police on Sunday meanwhile killed in Ankara two suspected members of the Islamic State jihadist group believed to have been planning an attack in the capital. But there was no indication of any link to the congress.