He said that the Continuity IRA had claimed responsibility for a blast at the Co. Fermanagh home of the peer, a member of the policing board for Northern Ireland.
"The Continuity IRA have telephoned a local newspaper claiming responsibility and a recognised code-word was used", he said. " We would all want to send a message of unswerving solidarity to a parliamentary colleague."
Lord Williams made his announcement before repeating the Prime Minister's statement on the situation in Northern Ireland.
