Radical Islamist Anjem Choudary is reported to have featured in a video that threatened UK Muslims, according to the Daily Telegraph.
Mr Choudary allegedly called David Cameron and Home Secretary Theresa May "pathetic foolish leaders".
The preacher told the newspaper: “I am happy for what I say anywhere in the world in any clip because at the end of the day I believe that I speak what is right according the divine texts.
“If they want to use that clip I don’t have any problem with that at all.”
UK-based imam and broadcaster Ajmal Masroor has written on his Facebook page that two Metropolitan police detectives arrived at his home on Wednesday night to warn he was "in imminent danger from the terrorists."
The police officers were visiting me to give me a warning and asking me to be more vigilant.
As soon as they left my house I started digging further and found an al-Shabab video has been uploaded on the internet and in it they name me as a Muslim who is an enemy of Islam and should be eliminated.
They name a few others in their video message and encourage people to resort to using knives to behead people like me.
Prominent Muslims in the UK received visits from the police after a video purportedly showing an al-Shabaab militant potentially making threats against them.
British Muslim commentator Mohammed Ansar and Mohammed Shafiq were among those reportedly targeted in the video.
Nice visit from the police at midnight to talk to me about the fact I'm in the latest al shabab terror video. Erm, as a potential target.
More security briefings tonight following threat by Al Shabaab against me and a number of prominent figures. This calls for more tea.
Thank you for all the concern, love and support I've received after al Shabab threats against me. I will never give into terrorism
Scotland Yard is investigating a video apparently made by Somali militant group al-Shabab after British Muslims who have spoken out against extremism were named as targets.
The hour-long film, narrated by an unidentified man with a British accent, reportedly praises acts of Islamist terrorism and starts by hailing the killing of soldier Lee Rigby in Woolwich, south east London.
The video singles out British Muslim commentator Mohammed Ansar as one of those who "distanced themselves" from those who carried out the attacks and as having "mutilated the teachings of Islam", according to reports.
He is one of a number of prominent Muslims to claim police have issued warnings to following credible evidence of potential threats against them.