A judge has ordered notorious US mob boss James 'Whitey' Bulger to be transferred to Boston to face federal charges, after his arrest in California ended a 16-year international manhunt.

The 81-year-old, arrested late yesterday in Santa Monica where he lived under pseudonym with his long-term girlfriend, confirmed his identity when he appeared at the brief court hearing.

'He was ordered by the court to be transferred to Boston... to face two federal indictments' with immediate effect, deputy US attorney Robert Dugdale told reporters outside the court.

The FBI said a recent publicity campaign had generated a tip that led agents to arrest Mr Bulger, 81, and his long-time companion Catherine Greig, 60, 'without incident'.

It did not provide further details on the circumstances of the arrest, which was made at a residence in Santa Monica, California, early yesterday evening.

Mr Bulger, who has been indicted for 19 murders, was the inspiration for Jack Nicholson's character in Martin Scorsese's film 'The Departed'.

The FBI began airing public service announcements on Tuesday that were focused on Ms Greig - a former dental hygienist said to frequent beauty salons - whom law enforcement agents believed would lead them to Mr Bulger.

It had offered a $100,000 reward for information on her whereabouts and a $2m reward for information leading to the arrest of Mr Bulger.

It was the largest reward the FBI has ever offered for a Top Ten domestic fugitive.

The FBI said on its 'Ten Most Wanted' website that Mr Bulger had been sought for a string of murders from the early 1970s to the mid-1980s 'in connection with his leadership of an organized crime group'.

It said his gang 'allegedly controlled extortion, drug deals, and other illegal activities in the Boston, Massachusetts, area'.

Mr Bulger had used a number of aliases during years on the run, the FBI said before the arrest, adding that he 'has a violent temper and is known to carry a knife at all times'.

The FBI said both Mr Bulger and Ms Greig, who is only accused of harbouring a known fugitive, would appear in court in Los Angeles today.

Before their capture in California, the last credible sighting of the pair was in London in 2002.

Mr Bulger is thought to have travelled extensively in the US, Europe, Canada and Latin America.