BELFAST (Reuters) - Irish nationalist party Sinn Fein on Monday suspended one of its lawmakers over an “indefensible” tweet on the anniversary of the day 10 Protestant textile workers were shot dead in 1976, which police blamed on the IRA.

FILE PHOTO - Sinn Fein Members of Parliament (MPs) Barry McElduff, Chris Hazzrd, Elisha McCallion, Paul Maskey, Michelle Gildernew, Mickey Brady and Francie Molloy, and Sinn Fein politician Pearse Doherty, attend a news conference in central London, Britain June 13, 2017. REUTERS/Hannah McKay

Sinn Fein, which wants to enter government in both Northern Ireland and the Republic of Ireland, has struggled to distance itself from the violent legacy of the Provisional Irish Republican Army (IRA), its ex-military wing, which waged an insurgency against British rule in Northern Ireland until 1998.

Barry McElduff, who last year was elected to the British parliament, posted a video on Twitter on Friday, the anniversary of the massacre near the village of Kingsmill in which he balanced a loaf of Kingsmill brand bread on his head. He later deleted the tweet.

Alan Black, the only survivor of the massacre in which Irish nationalist gunmen forced workers from a minibus and shot them dead at close range, told the BBC the video was “depraved” and designed to hurt relatives of the victims.

No one has ever been convicted for the crime, which an inquiry said was carried out by the IRA who targeted the men because of their religion. The IRA denied involvement.

“What has happened is inexcusable, it’s indefensible and the party is taking this matter very seriously,” Sinn Fein Chairman Declan Kearney told Irish state broadcaster RTE on Monday, alluding to McElduff’s tweet.

After a meeting with Sinn Fein’s Northern Ireland leader Michelle O’Neill, McElduff said in a statement that he had been suspended from all party activity for three months.

“Although I genuinely meant no offence, I accept that my actions were ill-judged and, while unintended, caused deep and unnecessary hurt and pain to the Kingsmill families,” he said.

The Police Service of Northern Ireland said on Saturday it was making inquiries following complaints about the tweet.

The 1976 massacre was one of a series of tit-for-tat attacks by Protestant paramilitaries who wanted Northern Ireland to remain British and Catholic Irish nationalists who sought a united Ireland.

The 1998 peace agreement paved the way for a power-sharing government and mostly ended the cycle of violence, though some small armed groups remain.