A spokesman for Nick Clegg said an Algeria-related tweet sent from Lib Dem MEP Graham Watson's account was "sick and offensive."
We have not been able to verify whether this tweet is authentic.
But whoever it is from, it is clearly sick and offensive and utterly condemned by Nick Clegg.
The tweet, since deleted, read: "Al Qaeda 1, @David_Cameron 0".
I'm told Mr Clegg was "furious" when he heard about the message. The party is still stressing, however, that they can't be sure Mr Watson himself sent it.
More top news
Murray's hopes of a first Australian Open title blew up in smoke as the world number one tumbled out in the fourth round to Mischa Zverev
The Pope has warned against a rise in populism and the danger of 'seeking a saviour in times of crisis'.
Gulf War veteran Paul Briggs' widow, Lindsey, 40, launched legal action to have his life support withdrawn so he could "die with dignity".