A Sudanese diplomat arrested on suspicion of sexually abusing a female subway rider in New York has avoided being charged by claiming diplomatic immunity.

Mohammad Abdalla Ali, 49, who is a member of the Sudanese mission to the United Nations, was arrested after he was allegedly grinding against a woman on the subway on Monday.

Ali was arrested at the scene after the 38-year-old woman complained. But after he showed his diplomatic credentials, detectives were forced to release him.

Sudanese diplomat Mohammad Abdalla Ali was accused of sexually abusing a woman on the subway leaving Grand Central Station in New York, file photograph, yesterday afternoon

Ali is accused of approaching the woman from behind and 'grinding' her with his crotch

The diplomat was taken to the Midtown South police station where he was charged with forcible touching and sexual abuse.

It is alleged Ali rubbed his crotch against the woman as the subway pulled out of Grand Central Station.

According to the Daily News the woman was approached from behind at 2pm as the northbound No. 4 train entered the tunnel.

A source told the newspaper: 'There's not much you can do. He has diplomatic immunity.'

The US State Department told MailOnline: 'We are aware of allegations of a criminal act by a Sudanese diplomat that led to the involvement of the NYPD. We are in touch with the NYPD and the Mayor’s office so that we are able to take appropriate steps, as needed, to address this matter.'

MailOnline has approached the United Nations and the Sudanese delegation to the UN for a comment in connection with the allegations.

How diplomatic immunity works Foreign diplomats are protected from prosecution under the 1961 Vienna Convention. The level of immunity afforded diplomats depends entirely on their rank, although according to Article 29 of the convention, a diplomat must not be arrested, nor can his home, office or car be searched. The person of a diplomatic agent shall be inviolable. He shall not be liable to any form of arrest or detention. The receiving State shall treat him with due respect and shall take all appropriate steps to prevent any attack on his person, freedom or dignity. Article 29 of the 1961 Vienna Convention However, later articles allow for a diplomat to face prosecution in his home nation having been accused of an offence while abroad. Also, it is possible for the diplomat's government to revoke the immunity and allow prosecution. Under Article 9 of the Convention, the hosting nation can declare any member of the diplomatic staff 'without having to explain its decision... persona non grata' and send them home. Advertisement