NEW YORK — Mayor Bill de Blasio said April 28 neither he nor his advisers did anything wrong despite his office confirming a day earlier that top aides received subpoenas by Federal and state prosecutors amid investigations into his campaign fundraising operation.

A series of loosely related public corruption investigations coordinated by U.S. Attorney Preet Bharara have trained a spotlight on de Blasio’s Administration, plunging City Hall into a political crisis, generating days of scathing tabloid front pages and sinking his poll numbers.

De Blasio, a Democrat serving his first term as Mayor, has not been accused of wrongdoing and insists his team did not violate any campaign finance laws.

“Everything we’ve done from the beginning is legal and appropriate,” de Blasio said as he was hounded by reporters after leaving a photo-op. “There’s an investigation going on. We’re going to fully cooperate with that investigation.”

The latest development in the overarching probe, which has slowly played out for most of April, was the news late April 27 that subpoenas were delivered to several top de Blasio associates and to groups closely linked to him.

The Mayor’s top spokeswoman, Karen Hinton, confirmed the subpoenas were delivered to Emma Wolfe, de Blasio’s top political aide; his campaign fundraiser Ross Offinger; consulting firm Berlin Rosen and the non-profit organization Campaign for One New York, which advanced de Blasio’s political agenda.

De Blasio, asked by WABC-TV if he was subpoenaed, said: “I was not.”

The investigation, jointly run by the U.S. Attorney’s office for New York’s Southern District and by Manhattan District Attorney Cy Vance Jr., is examining de Blasio’s efforts to help Democrats win the state Senate in 2014 and whether donors to his campaign or the nonprofit received city benefits in exchange for donations.

Neither Wolfe nor Offinger responded to requests for comment. Jonathan Rosen, the head of Berlin Rosen and a close de Blasio ally, said in a statement, “We have acted appropriately and in accordance with the law at all times.”

The probe has become politically perilous for de Blasio, who in recent days has ducked reporters by sneaking into events by freight elevators and using his security team to keep inquisitors at bay.

De Blasio, who had an up-and-down first two years in office, landed a major victory for his housing plan this year in the City Council and saw his poll approval numbers creep above 50 percent for the first time in months.

His team had hoped to focus on the nuts and bolts of governing this year and allow the Presidential election to dominate the political headlines until he was ready to focus on his re-election bid in 2017.

Instead, de Blasio has seen his approval rating sink to new lows, perhaps emboldening potential primary challengers, and has received scornful tabloid coverage, becoming the subject of headlines such as “deBacle” in the New York Post and “Bull de Blasio!” from the Daily News.

The probe appears to have begun after the top investigator at the state’s Board of Elections, Risa Sugarman, asked prosecutors in January to investigate whether the Mayor’s advisers broke the law by channeling campaign contributions to Democratic state Senate candidates through a committee not subject to donation limits, so as to evade them.

De Blasio has called the Board of Elections report outrageous, and his campaign attorney wrote to the board’s chief enforcement officer insisting the law allowed the types of donations in question. His allies have suggested similar tactics have been used by other top New York politicians.

Additionally, an animal welfare group that has lobbied de Blasio to ban carriage horses from city streets said last week it had received from Federal prosecutors a subpoena that sought documents relating to its fundraising efforts for the Campaign for One New York.

The Mayor announced in March he was shutting down the Campaign for One New York, launched in 2014. The organization had come under fire from good-government advocates over its receipt of large donations from companies lobbying City Hall.

Prosecutors also are looking into the fundraising activities of businessmen with ties to the Mayor and a Manhattan nursing home land deal. Other investigations concern high-ranking New York Police Department officials and the union representing city jail guards.

A City Hall spokesman did not respond late April 28 to questions about whether others tied to de Blasio have received subpoenas.

___

By Jennifer Peltz and Jonathan Lemire. AP writer Michael Balsamo contributed