Northern Ireland First Minister Michelle O'Neill said her attendance at a police graduation ceremony "fulfils" her commitment to be first minister for all.
It was the first time there has been Sinn Féin participation in the event since the PSNI was founded 23 years ago.
Ms O'Neill arrived to watch a small number of constables complete their training and move into full time roles.
Speaking at the event in Belfast, Ms O'Neill said: "It's a great day for the six graduates who have now been attested this afternoon and I wish them the very best for their future career in policing.
"I think it's so important that our policing service reflects the diversity of our society that we have, so I wanted to be here and be part of wishing these new constables the very best in their journey.
"I became First Minister last Saturday. I said I would be a first minister for all and that includes these new constables who have graduated today.
"I also think it fulfils my commitment of being first minister for all. When the invite came in for today, I wanted to be here because it is such an important time."
Ms O'Neill was accompanied by her party colleague and Policing Board representative Gerry Kelly.
Deputy First Minister Emma Little-Pengelly and Justice Minister Naomi Long also attended.
Sinn Féin's attendance is being seen as significant and the final act in the party's unambiguous acceptance of the changed policing structures.
Sinn Féin endorsed policing in 2007, has served on the policing board for years and publicly backed a recruitment campaign in 2020.
Today I was glad to attend the graduation of new police recruits.
— Michelle O'Neill (@moneillsf) February 9, 2024
I offered my congratulations as they embark on their policing careers.
It was nice to meet them personally, and their families.
I wish them well as they play their part in bringing about safer communities. pic.twitter.com/OalMBqdMzk
Over the years there have been several high-profile joint appearances with the Chief Constables of the day.
The most memorable was that of then deputy first minister Martin McGuinness who referred to dissident republicans as "traitors to the island of Ireland" after the 2009 murder of a police constable.
He stood alongside PSNI Chief Constable Hugh Orde as he said it.
Stephen Carroll was gunned down by the Real IRA in Lurgan in March 2009.
Sinn Féin objections to the passing out ceremony were linked to a critical 2016 internal review of the policing college regime, which said at times it resembled a military style boot camp.
It described it as "pseudo militaristic" with students marching to and from classes.
PSNI Chief Constable Jon Boutcher said the attendance of the First Minister at today's event was a "hugely positive gesture".
He said the police service had been contacted earlier this week asking whether Ms O'Neill could attend.
Relations between Sinn Féin and the PSNI were affected during Covid, when a survivor of a loyalist gun attack was arrested at a commemoration event.
The party denied it had threatened to withdraw support for policing as a result.
The controversy eventually led to the resignation of chief constable Simon Byrne and his replacement with Mr Boutcher.
Mr Boutcher said he was pleased to see Sinn Féin attend the ceremony today.
"With the restoration of the Assembly, now is the time to grasp the opportunity to work together, rather than have policing as a political football.
"I am determined for the security and safety of the people in Northern Ireland, that such future events will have the officer numbers we need to keep Northern Ireland safe, rather than the small yet important number of officers attesting today."
The PSNI is facing massive budgetary pressure and is struggling to get the numbers of police officers to the recommended 7,500.
It is currently around 1,000 officers below that number.
It has also struggled to increase recruitment from the Catholic community, which currently makes up 32% of serving officers, but accounts for 46% of the population.
Additional reporting PA
