LONDON (AFP) - A man arrested outside Queen Elizabeth II's Buckingham Palace residence for allegedly attacking police with a sword appeared in a London court on Thursday (Aug 31) charged with a terror offence.

Mohiussunnath Chowdhury, 26, appeared at London's Westminster Magistrates' Court wearing grey track top and bottoms, speaking to confirm his name, age and address.

He is accused of "engaging in conduct in preparation for giving effect to his intention to commit an act or acts of terrorism", Scotland Yard said in a statement.

Chowdhury, from Luton, north of London, was arrested outside the palace gates on Friday.

Three police officers suffered minor injuries after he allegedly drove a blue Toyota Prius car at officers outside Buckingham Palace and then reached for a 1.2m-long sword.

He allegedly shouted "Allahu Akbar" as he reached for the sword before being disabled with CS gas, the court heard.

He was charged with an offence contrary to the Terrorism Act 2006 and will appear again at London's Old Bailey on Sept 21.

Police investigating the attack released a second suspect from custody on Wednesday with no further action.

"We believe the man was acting alone and we are not looking for other suspects at this stage," said Dean Haydon, the head of Counter Terrorism Command.

"While we cannot speculate on what the man was intending to do - this will be determined during the course of the investigation - it is only right that we investigate this as a terrorist incident at this time."

In Britain, 35 people have been killed in three Islamic terrorist attacks in London and Manchester since March.