New Jersey Governor Christie: 'We let down the people'

Embattled New Jersey Governor Chris Christie has pledged to co-operate with inquiries into a series of scandals threatening his political future.

It has been revealed his senior staff orchestrated a severe traffic jam at the foot of a major bridge in an act of apparent political payback.

"We let down the people we are entrusted to serve," he said in a major speech, referring obliquely to the row.