Jeffrey Donaldson, the leader of Northern Ireland's main pro-UK Democratic Unionist Party (DUP) and one of its best-known politicians, resigned on Friday after police reportedly charged him over historical sex offenses.

Earlier in the day, media outlets had reported that his imminent resignation was linked to a statement from Northern Ireland police saying two people had been charged "about non-recent sexual offenses".

The shock development comes at a pivotal moment for the British territory, just weeks after the restoration of devolved power-sharing following the end of the DUP's two-year boycott of the Stormont Assembly.

The resumption of power-sharing led to Sinn Fein's Michelle O'Neill making history by becoming Northern Ireland's first pro-Irish nationalist leader.

The DUP said Donaldson had confirmed in a letter to the party's chairman that he had been "charged with allegations of a historical nature" and that he was resigning as a leader "with immediate effect".

"By the party rules, the party officers have suspended Mr Donaldson from membership, pending the outcome of a judicial process," it added.

The DUP statement, which followed an emergency party meeting, did not refer to the nature of the alleged offenses.

Party officers had unanimously appointed deputy leader Gavin Robinson, another DUP lawmaker in the UK parliament, as interim leader, it added.

Hours before Donaldson's sudden resignation, several of the 61-year-old's social media accounts were abruptly deleted.

Earlier on Friday, numerous media outlets reported that his imminent resignation was linked to a statement by the Police Service of Northern Ireland (PSNI) reporting two arrests without identifying those charged.

"A 61-year-old man has been charged with non-recent sexual offenses," said a PSNI statement.

"A 57-year-old woman was also arrested and charged at the time for aiding and abetting additional offenses.

"Both are due to appear before Newry Magistrates' Court on 24 April," it added.

  Long-serving MP 

 Donaldson, a longtime player in Northern Irish unionist politics, became DUP leader in 2021.

The party walked out of the power-sharing government at Stormont in February 2022 in protest over post-Brexit trade arrangements for Northern Ireland, which has the UK's only land border with the European Union.

It argued the trade terms, agreed to avoid a so-called hard border with the Republic of Ireland to the south, risked cutting the territory adrift from the rest of the United Kingdom.

But its boycott of the assembly paralyzed Northern Ireland's public services and fuelled both political uncertainty and industrial unrest.

Donaldson announced in February that the party now backed a deal with the UK government in London to break the deadlock, paving the way for Stormont to be restored.

In turn, that saw O'Neill become Northern Ireland's first minister.

The appointment of a Roman Catholic, pro-Irish unity leader in a nation set up as a Protestant-majority state under British rule was hailed as hugely symbolic.

The DUP's Emma Little-Pengelly became her deputy.

Under the 1998 Good Friday Agreement, which largely ended decades of sectarian violence over British rule in Northern Ireland, the first minister and deputy first minister posts are equal.

As well as being the second largest party in the Northern Irish assembly -- behind Sinn Fein -- the DUP had eight MPs in the UK parliament in Westminster.

Donaldson's suspension means he will now sit as an independent and reduces that number to seven.

He is the longest-serving MP with a Northern Irish constituency, having been first been elected in 1997.

He had been expected to lead the DUP into the next UK general election, likely to take place later this year.

Donaldson was recognized by the late Queen Elizabeth II in 2016 when he received a knighthood.