New York's attorney general has sued US President Donald Trump and his namesake foundation, saying the nonprofit should be dissolved after more than a decade of illegal conduct, including support for Mr Trump's 2016 US presidential campaign.

Barbara Underwood, the attorney general, accused the Donald J Trump Foundation and its directors of conducting "extensive unlawful political co-ordination" with the campaign, and "repeated and wilful self-dealing" to benefit Trump's personal and business interests.

"The Trump Foundation was little more than a checkbook for payments from Mr Trump or his businesses to nonprofits,regardless of their purpose of legality," Ms Underwood said in a statement. "That is not how private foundations should function."

The foundation could not be immediately reached for comment.

However, Mr Trump is reported to have said he will not settle the case against his organisation.

His children were also named as defendants in the attorney general's petition, filed with the New York State Supreme Court in Manhattan.

New York is also seeking $2.8m of restitution plus penalties, a ten-year ban on Mr Trump serving as a director of a New York nonprofit, and one-year bans for his children Donald Jr, Eric and Ivanka.