A 29-year-old British man has been charged in Kenya with possessing illegal explosive-making material and plotting to explode a bomb.
Jermaine Grant and his three Kenyan co-accused denied the charges.
Mr Grant, arrested in Mombasa last month, has already been jailed for a year for being in Kenya illegally.
Earlier this week, police spokesman Eric Kiraithe told the BBC that he was being questioned about possible links to the Somali Islamist group al-Shabab.
"Such information could also assist us in preventing any possible al-Shabab threat," Mr Kiraithe said.
In October, Kenya sent troops into Somalia to pursue the al-Qaeda linked group, blaming it for a recent wave of abductions which threatened its tourism industry.
Al-Shabab, which controls much of south and central Somalia, denied any involvement and said the Kenyan incursion was an act of war and it would take revenge.
Ordered to uncover faces
The BBC's Jamhuri Mwavyombo in the Kenyan coastal city of Mombasa says Mr Grant appeared in court with three Kenyan co-accused, two men and a woman.
The charge sheet said as well as possessing bomb-making equipment, they planned to improvise an explosive device with the intention of causing loss of life and harming innocent civilians.
Three of the defendants were remanded in custody until the case reconvenes on 20 February, while the woman was granted bail of $228,000 (£149,000), our reporter says.
When they entered the courtroom the judge ordered them to stop covering their faces from photographers. After this Mr Grant kept his head down, she says.
Mr Grant, from Newham in east London, was arrested by police in Mombasa before Christmas and pleaded guilty to being in the country illegally and giving false information.
Over the weekend, the UK updated to its travel advice on Kenya, warning that extra care should be taken if travelling in the East Africa country as there were threats of an imminent terror attack.