The man known as 'Mr Clean' who is tasked with cleaning up the streets of San Francisco and tackling its homelessness crisis has been charged with corruption, after an FBI probe.

Mohammed Nuru, San Francisco's Director of Public Works, was arrested by the FBI for a series of alleged public corruption schemes, authorities said on Tuesday.

In his role, Nuru, 58, is tasked with keeping the city of San Francisco clean, including cleaning up trash, removing vandalism, repairing sidewalks, and tackling the city's homelessness crisis.

He has been charged with one count of wire fraud for allegedly attempting to bribe an airport commissioner to win a bid for a restaurant contract at San Francisco International Airport.

Mohammed Nuru (above), San Francisco's Director of Public Works, was arrested and charged by the FBI for public corruption Tuesday

Nuru, 58, (right) and Nick Bovis, 56, (left) a well-known local restaurant boss, have been charged with allegedly attempting to bribe an airport commissioner to win a bid for a restaurant contract at San Francisco International Airport

Bovis (above) is a well-known local restaurant boss and a donor to Mayor London Breed's 2018 mayoral campaign

Nick Bovis, 56, a well-known local restaurant boss has also been arrested and charged on the same count.

U.S. Attorney for the Northern District of California David Anderson said at a press conference that the FBI investigation had uncovered a 'web of corruption'.

'The complaint describes a web of corruption involving bribery, kickbacks, and side deals by one of San Francisco's highest-ranking city employees,' said Anderson.

'The public is entitled to honest work from public officials, free from manipulation for the official's own personal benefit and profit.'

Nuru, who dubbed himself 'Mr Clean', was arrested last week and released on the condition that he would cooperate with the FBI investigation and would not tamper with or disclose the investigation, according to the San Francisco Examiner.

The public servant was arrested again Monday after breaking the conditions by disclosing the probe to others.

He has since been charged with an additional count of making false statements.

Nuru's arrest is the latest in a string of scandals and allegations of corruption to hit the public servant.

In 2004, before entering the public works office, it came to light that his nonprofit organization the San Francisco League of Urban Gardeners was forcing employees to support the campaigns of then-Mayor Gavin Newsom and former District Attorney Kamala Harris.

The City Attorney's Office also accused the organisation of dodgy accounting practices and improper use of city grants.

Then in 2011, Nuru was accused of sexism and racism against black women in a workplace lawsuit. A settlement was reached before the case went to court.

U.S. Attorney for the Northern District of California David Anderson (right of FBI Special Agent John Bennett) said at the press conference that the FBI investigation had uncovered a 'web of corruption'

'The public is entitled to honest work from public officials, free from manipulation for the official's own personal benefit and profit,' said Anderson (above)

The FBI has been investigating Nuru and Bovis since 2018 through wiretaps and undercover officers.

The main alleged corruption uncovered was attempted bribery of an unnamed SFO commissioner in exchange for a restaurant contract at the airport.

According to officials, Nuru and Bovis said they would give the commissioner $5,000 and free travel in exchange for her vote to approve a contract for Bovis' restaurant Spinnerie.

The complaint says the commissioner dismissed the bribes.

In recorded conversations between Bovis and an FBI undercover officer, the complaint shows that Bovis grew suspicious that the FBI may be investigating the pair.

'Well, in my brain, what if this is some sort of FBI sting or something?' Bovis reportedly said.

Nuru (above) who dubbed himself 'Mr Clean', was arrested last week and released on the condition that he would cooperate with the FBI investigation and would not tamper with or disclose the investigation. He was rearrested Tuesday after he broke the conditions

Four other allegations of corruption continue to be investigated, authorities said.

It includes one where Nuru is believed to have provided Bovis with insider information to bid on contracts for providing mobile housing and toilets for homeless people across the city.

Since becoming director of Public Works in 2011, Nuru has come under fire for a lack of progress in tackling the city's homelessness problem.

The so-called Mr Clean has struggled to clean up the city, with trash, used needles and human feces a big issue.

Public officials have given a mixed response to news of his arrest.

Aaron Peskin, supervisor on the San Francisco Board of Supervisors, said the news was 'explosive' and 'extremely disturbing.'

It 'implicates not only the individuals that we've heard who were arrested but many other people, including commissioners and developers,' Peskin said.

'I feel ashamed for the city and county of San Francisco that this could be going on and I think the mayor and the board has some investigating to do and some house cleaning to do.'

Supervisor Matt Haney commented that Nuru had a lot of power at Public Works and that the department lacked transparency.

'It was well-known everything ran through Mohammed,' Haney told the San Francisco Examiner.

Since becoming director of Public Works in 2011, Nuru has come under fire for a lack of progress in tackling the city's homelessness problem (pictured)

The so-called Mr Clean has struggled to clean up San Francisco, with trash, used needles and human feces a big issue

Mayor London Breed, who received a donation from Bovis in 2018 towards his mayoral campaign, issued a statement saying the allegations were 'extremely serious' and that the city attorney would be conducting 'a thorough review of any implicated city contracts or other decisions'.

Nuru has been placed on administrative leave.

Both defendants appeared in federal court Tuesday and were arraigned and released, each on a $2 million bond.

Nuru's attorney Ismail Ramsey issued a statement saying his client is a 'dedicated public servant' and 'looks forward to addressing these charges in court'.

If convicted, Nuru and Bovis could face up to 20 years in prison.