RTÉ was left embarrassed and "infuriated" after it suffered a technical glitch during its broadcast of Prime Time last night.

During an interview with Russian Ambassador to Ireland Maxim Peshkov on the crisis in the Ukraine, the phrase "Irish Ukrainians, not Russians" was played in a loop for up for 13 minutes .

The station received 79 calls and emails in relation to the fault.

Bemused viewers took to Twitter resulting in the the hashtag #irishukrainiansnotrussians trending in Ireland last night.

RTÉ News and Current Affairs managing director Kevin Bakhurst apologised on Twitter to viewers .

“The engineers were aware and trying to sort. Not acceptable fault. Infuriating,” he said. He said problem did not affect the HD channel.

RTÉ Primetime tweeted: “Many apologies for the enormous and embarrassing technical problem on PT tonight. Engineers were on to it straight away but difficult to stop.”

RTÉ issued a statement today to apologise for the blunder on the programme.

“(It) was caused by an equipment failure in hardware installed in December as part of the RTÉ One HD project.

“The automated system had to be manually overridden and this delayed the glitch being rectified.”