Chief Rabbi Lord Sacks issued a plea for "a continued prayer for peace, not only in Gaza but the whole region" - but later accused Iran of being part of the conflict, without realising he was live on Radio 4.
Lord Sacks told BBC Radio 4's Today programme: "No one gains from violence - not the Palestinians, not the Israelis. This is an issue where we must all pray for peace and work for it."
The Chief Rabbi was asked for his assessment of the situation in Gaza immediately after delivering the daily Thought for the Day on the programme.
He initially responded: "I think it's got to do with Iran, actually", before being told he was live on air, when he made his call for a prayer for peace.
The error caused some amused reaction on Twitter.