Ex-Plaid Cymru leader Lord Wigley has apologised after comparing the Trident base in Scotland to Auschwitz concentration camp.
He had been asked about the employment boost if the nuclear facility were to be moved to Wales.
He told the BBC: "No doubt there were many jobs provided in Auschwitz and places like that but that didn't justify their existence."
The comments come after the 70th anniversary of Auschwitz's liberation.
Scottish Secretary Alistair Carmichael described Lord Wigley's remarks as "offensive" to those who died and to those who worked at the Faslane naval base.
Lord Wigley, Plaid's general election co-ordinator, then released a statement saying: "I am certainly sorry if my remarks were open to any misinterpretation and I apologise for any offence that has been caused.
"The point I was trying to make was that you can't have jobs at any cost and I reiterate that."
Earlier the Ministry of Defence denied a report in the Scottish Daily Mail that the nuclear deterrent could be moved to Wales from the Faslane naval base on the River Clyde.
The Scottish National Party is opposed to Trident, but the MoD said it was "fully committed" to keeping it on the Clyde, adding: "We can be very clear the MoD is therefore not planning to move the nuclear deterrent from HM Naval Base Clyde to Wales, or anywhere else."
Plaid Cymru also wants Trident to be scrapped, and Lord Wigley rejected any possible employment benefits of it moving to Wales.
He said: "Look, this week we have been remembering what happened in Germany before the war, no doubt there were many jobs provided in Auschwitz and places like that but that didn't justify their existence and neither does nuclear weapons justify having them in Pembrokeshire."
Asked about the comparison, he added: "The number of people that will be killed by Trident will be infinitely more."
Lord Wigley went on to say he was making the point that "you have to consider the nature of the work and not just that a job exists".
Sir Menzies Campbell, the former leader of the Liberal Democrats, said Lord Wigley was a "passionate politician" but added: "This time he has gone too far and he should withdraw his comments immediately''.
Conservative MP and former welsh secretary David Jones said the apology was "mealy-mouthed".
He said: "His remarks were crass and bound to cause offense. While the apology is a bit mealy-mouthed, at least it is good that he has acknowledged they are offensive."
Scottish First Minister Nicola Sturgeon said it was "not language I would use", adding that it was "appropriate" he had apologised.