Al-Shabaab has claimed responsibility for the deadly attacks in Kenya yesterday.
In a statement, the Somali Islamist group said, "Commandos last night carried out a successful raid on the town of Mpeketoni."
As reasons, it cited the deployment of Kenyan troops to Somalia, and what it called Kenya's extra-judicial killings of Muslim scholars - a charge Nairobi has denied.
The UK Government says travelers should not go within 60km of the Kenyan border with Somalia unless absolutely necessary, because of the threat from terrorist group Al-Shabaab.
Yesterday's attack happened in Mpeketoni, just south of the popular resort of Lamu. This is not within the orange danger zone, though the Foreign Office has today updated its website to make travelers aware of the killings.
A spokeswoman at the Foreign & Commonwealth Office said the travel advice is kept under constant review.
Al-Shabaab, the Somali Islamist group with links to Al-Qaeda, has claimed responsibility for yesterday's attacks, according to the pro-Shabaab website Somalimemo.
It goes on to claim that the attacks were revenge for the killing of Muslim clerics.
Kenya sent troops to Somalia in 2011 to help the UN-backed government defeat Al-Shabaab.
Kenyan police say Somalia's Al-Shabaab Islamist group is most likely to blame for Sunday night's assault on the town of Mpeketoni.
There has been no immediate claim of responsibility for the attacks, in which at least 48 men were killed.
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.
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.
An Al-Shabaab recruitment video makes reference to 10 British militants, raising the possibility of links to the attack on a mall in Kenya.Read the full story ›
Pentagon press secretary George Little has confirmed a counter-terrorism operation "against a known al-Shabaab terrorist" but did not add any further details:
I can confirm that US military personnel were involved in a CT operation yesterday against a known al-Shabaab terrorist.