The NYPD commissioner has revealed it cost the city $25million to protectDonald Trump between his election victory and inauguration.

In a letter to New York City area members, James P. O'Neill described the challenge as being 'unique and unparalleled.'

During that time, Trump spent the majority of his time in his penthouse apartment at his eponymous tower.

Trump spent the majority of his time between his election victory and inauguration at Trump Tower (pictured on December 6)

There were a number of protests staged outside Trump Tower after Trump's election win

Mr O'Neill asked for Congress to reimburse the cost for securing Trump Tower during the presidential transition.

He also requested future funding for protecting the glitzy Manhattan skyscraper and to ensure there are enough resources to keep the city safe.

He said the police department now had a dual role in protecting the first family while also serving residents in the city.

He wrote: 'Trump Tower, a 58-story mixed-use building in midtown Manhattan, is located along a highly trafficked corridor of Fifth Avenue in a dense urban environment that comprises large hotels, world renowned department stores, and some of the city's most iconic tourist attractions.

'Such a setting for the second residence of an American President is unique in recent history.'

He added: 'Trump Tower itself now presents a target to those who wish to commit acts of terror against our country, further straining our limited counterterrorism resources.'

Mr O'Neill said he expected the NYPD to spend between $127,000 and $146,000 per day protecting First Lady Melania Trump and her son, Barron, while they reside in Trump Tower

O'Neill revealed that having police and fire officials protect Trump's family, home and office for the 75 days between Election Day and Inauguration Day came to a total of $25.7 million.

That was less than the $35 million the police had initially estimated.

O'Neill said he expected the NYPD to spend between $127,000 and $146,000 per day protecting First Lady Melania Trump and her son, Barron, while they reside in Trump Tower.

This is in addition to an annual bill of $4.5 million for the city's fire department to protect Trump's wife and 10-year-old son.

The pair are staying in New York until at least the end of the school year.

Those costs, Mr O'Neill said in the letter on Tuesday, will 'increase significantly' whenever the president is in New York City.

The police department anticipates an average daily rate of $308,000 on the days when the billionaire former reality TV host is in the Big Apple.

Trump has not returned to New York City since moving into the White House on January 20.

New York Congresswoman Carolyn Maloney in a statement on Wednesday the city's taxpayers should not be forced to pay for a 'national security obligation' and that 'Congress must provide city taxpayers a full reimbursement.'

Senator Chuck Schumer of New York said: 'It's simply unfair to have New York City taxpayers alone bear the burden of NYPD protection at Trump Tower.'

It comes after Trump's family's trips were reported to have cost taxpayers nearly as much in a month as Barack Obama's cost in an entire year.

The US President's three visits to his Mar-a-Lago club in Florida since his inauguration, combined with his sons' business trips, were said to have cost $11.3m.

Conservative watchdog Judicial Watch estimated Obama's travel expenses totaled an average of $12.1m in each of his eight years in the White House.

Tom Fitton, Judicial Watch's CEO, said: 'The president is going to have to be sensitive to the cost of travelling around. I appreciate he wants to go home to Mar-a-Lago every weekend but it is costly to do so and the work he does there he can do elsewhere.'

A Trump spokesman could not be reached immediately for comment.