R&B singer Chris Brown has been denied a visa to enter the country just days before his UK tour was due to start.

The US star, who was sentenced to six months community labour for assaulting then-girlfriend Rihanna last February, was due to kick off his tour in Glasgow on Wednesday night, before playing at the 02 Academy, Birmingham, on Thursday.

Brown, 21, has been refused permission on the grounds of being guilty of a serious criminal offence, the Home Office said.

Tour promoters SJM said the concerts had been "postponed" and that dates to see the Run It! and Kiss Kiss singer would be rescheduled.

He was also due to perform in Birmingham, Manchester and London's Hammersmith Apollo on Thursday, Friday, and Sunday respectively, and in Ireland next Tuesday.

The Home Office said in a statement: "We reserve the right to refuse entry to the UK to anyone guilty of a serious criminal offence. Public safety is one of our primary concerns.

"Each application to enter the UK is considered on its individual merits," it added.

Brown was sentenced in August last year to five years probation, 180 days community labour and told to attend a domestic violence programme. He was also told to stay at least 100 yards from Rihanna for the next five years.

Brown submitted his visa application on June 1 and would have learnt on Monday that it had been refused.

Tour promoters SJM said: "Due to unforeseen circumstances the Chris Brown UK tour ... has unfortunately been postponed. Ticket buyers should hold on to their tickets as there will be more news in the forthcoming days of possible rearranged dates."