A state assemblywoman Diana Richardson, from Brooklyn has been arrested after her injured 12-year-old son accused her of hitting him with a broomstick, ­police sources said.

Richardson faces charges of assault, endangering the welfare of a child, criminal possession of a weapon and menacing after she admitted beating her son sources said.

Her son, who is not being named, had walked into the NYPD's 71st Precinct on Friday night where he showed officers a contusion on his arm, New York Post reports.

He claimed that his mother had beaten him with a broomstick after they got in an argument over his report card.

Richardson — who on social media calls her son her “greatest accomplishment” —was taken to the station house the next day and admitted to beating the boy because he had pushed her during the argument, the sources said.

She admitted that they had fought after he refused to complete an essay on how to improve his grades, the sources said.

The boy grew enraged and pushed her, she reportedly claimed. .

His 33-year-old mother was arrested at her Crown Heights home at about 1am on Saturday. She was released without bail and is due back in court on January 10 next year.

Richardson in a Facebook post had previously admitted to her son being difficult.

'I am so grateful for this young man...my right hand...my everything,' she said, adding, 'He is a pain in my side but I love him anyway!' she wrote in January 2015.

Colleagues were shocked to hear the news, describing her as a 'wonderful parent'.