MMA fighter Conor McGregor has hit out at the Irish actor Liam Cunningham in an online row over the Gaza-bound aid boat Madleen.

Israeli naval forces boarded and seized the vessel carrying 12 people, including Swedish activist Greta Thunberg and French MEP Rima Hassan, that had tried to break a naval blockade of the war-torn Gaza Strip earlier today.

The British-flagged yacht operated by the pro-Palestinian Freedom Flotilla Coalition (FFC) aimed to deliver a symbolic amount of aid, including antibiotics and baby formula, to Gaza and raise awareness of the crisis.

However, the vessel was boarded during the night before it could reach shore, the FFC said on Telegram, while the Israeli Foreign Ministry confirmed the boat was under Israeli control.

Mr Cunningham, best known for his role as Davos Seaworth in HBO’s series Game of Thrones, has shared several tweets in the wake of Israel seizing the aid boat.

The Dublin actor, who has been vocal about his support for Palestine, helped launch the vessel carrying humanitarian aid to Gaza in Catania, Italy, on Sunday, June 1.

Shortly after, Conor McGregor responded to the actor’s tweet on X, saying: "I thought you were on this boat Liamo, what happened?”

"You forgot your goggles? You get seasick off the gargle? Bottler,” McGregor added, to which Cunningham responded: "Didn’t know you could read and write, Conor. Thought you used your hands to tap out.”

The MMA fighter then uploaded a picture depicting Greta Thunberg, which was originally posted by the Israeli Foreign Ministry.

In a separate tweet, McGregor said: “Tell us you’re plotting an Irish goodbye without telling us.”

"Two bags full packed and ready to skid! Ah Liamo you little bottler!” he added.

His post was accompanied by a picture of Liam Cunningham during the Madleen launch in Sicily with activists Thiago Ávila and Yasemin Acar, who are both onboard the vessel.

He later added: "For the record, Liam Cunningham is a virtue signaling bottler. He was right there and did not go. That is absolutely embarrassing.”

Speaking last week at the launch of a new People Before Profit pamphlet “No To War – Defend Irish Neutrality”, published in opposition to Government plans to change the triple lock system for overseas deployments, Cunningham said that it was never planned that he would be on the Madleen boat as it is a small vessel, RTÉ reported.

He also said the Irish Government is “siding with warmongers” while the actor endorsed an opposition campaign to “defend Irish neutrality”.

Under the current system, Ireland cannot deploy more than 12 Defence Forces peacekeepers overseas without a mission being approved by the UN, the Government and the Dáil.

As part of the draft legislation being advanced by the Government, it is proposed to remove the requirement for formal UN approval and replace it with a stipulation that the deployments are in accordance with the UN Charter.

The Government argues this will prevent the five permanent members of the Security Council – Russia, China, the UK, the US and France – from exercising their veto against Irish peacekeeping missions.

However, Mr Cunningham accused the Government of “lying” and “obfuscation” over the mechanics of the existing triple lock, adding that the current system allows the UN General Assembly to approve such a mission in the absence of a green light from the Security Council.