Suspicious letter addressed to US President Obama has tested positive for the deadly poison ricin, as did a letter to a Republican Senator.
The FBI assessment is that there are no links between the poison letters to Obama and Senator Roger Wicker and the bombs at The Boston Marathon.
More top news
The PM urged Tory MPs not to side with Jeremy Corbyn by opposing British airstrikes against Islamic State in Syria, ahead of a Commons vote.
Armed police have taken part in a dramatic training exercise aimed at recreating the chaos of a Paris-style terror attack.
After a remarkably mild November - a notable mild start to the new month.