The Twitter account of Somali militant group al-Shabab has been suspended for a second time. A message from Twitter on the @HSMPress1 account said it had been suspended, without elaborating. In a statement sent to the AFP news agency, the group denounced the move, calling it "futile". On Tuesday, the al-Qaeda-linked group used Twitter to claim it had ambushed the convoy of President Hassan Sheikh Mohamud, who was unhurt...Twitter has a policy in which accounts can be suspended if users publish threats of violence. They are also blocked if they use Twitter for unlawful purposes or illegal activities...The group's previous English account, @HSMPress, was suspended in January after it was used to threaten to kill Kenyan hostages...Analysts have said that in the past the United States has attempted to close the al-Shabab account, but had lacked the legal means to force Twitter to do so.