UK parliament attack: Police make another arrest in investigation

Police have arrested a 30-year-old man in the central English city of Birmingham in connection with last week's attack on parliament, "on suspicion of preparation of terrorist acts", the Metropolitan Police said on Sunday.

The police said in a statement they had arrested 12 people since Wednesday's attack when British born Khalid Masood killed four people and was himself shot dead. But nine had been released with no further action, the police added.

Police are trying to find out what motivated Masood, 52. He used a hired car and kitchen knife, and officials say such attacks are hard to prevent.  Masood, 52, was born in the county of Kent in southeast England and was most recently living in the West Midlands region of central England.

"Masood was not the subject of any current investigations and there was no prior intelligence about his intent to mount a terrorist attack," the Metropolitan Police said in a statement. "However, he was known to police and has a range of previous convictions for assaults, including GBH (grievous bodily harm), possession of offensive weapons and public order offences."

Lawmakers are increasingly concerned about their security, with some reporting abuse on social media over Brexit after Britain's vote to leave the European Union revealed deep divisions in the country.