As Mayor London Breed braces for the potential fallout from her disclosure last week that she accepted $5,600 in gifts from ex-Public Works Director Mohammed Nuru, she admitted to a lapse in judgment that allowed her personal life to bleed into her professional one.

Breed laid out what happened in an online post Friday, but her attempt at transparency still left many questions unanswered.

On Tuesday, Breed remained tight-lipped when pressed for details in an interview about why Nuru, a prominent department head, paid for a mechanic to repair Breed’s broken-down car and for a rental car last year.

“I asked my friend Mohammed to get rid of the car, and it didn’t happen that way,” Breed told The Chronicle. “I don’t want to go into details, but I’m here to take full responsibility for what happened because I didn’t handle it well.”

Breed’s adversaries are unlikely to be placated by her contrition. The gifts, her critics maintain, represent a clear breach of the city’s ethics laws, which limit managers from receiving gifts from subordinates.

Breed also wrote Friday that she and Nuru were longtime personal friends and that they briefly dated two decades ago.

It remains unclear why the mayor, who has the use of a driver and a security detail, needed to invest in repairing an 18-year-old car that she said she didn’t use and wasn’t working. Those were among the details Breed declined to delve into on Tuesday.

Revelations about the gifts are playing out against the backdrop of the ongoing FBI investigation into government corruption in San Francisco, an inquiry that’s already led to federal fraud charges against Nuru and restaurateur Nick Bovis. The city attorney’s office is also leading a separate, internal probe into the extent of any potential self-dealing tied to allegations surrounding Nuru.

Breed told The Chronicle on Tuesday her longtime friendship with Nuru, who resigned last week, obscured the potential pitfalls of allowing a department head to foot the bill for her car repairs and the rental.

“Part of it is, this is my personal life. I didn’t see it the way others see it,” Breed said. “What all this has forced me to do is to re-evaluate my friendships. It’s a learning experience. I have to think differently about relationships — my family, my friends and honestly, who I date, too.”

Though Breed has been an elected official for years, the ordeal has taught her a hard lesson, she said, about the need to separate her personal and professional lives.

“Just because I’m the mayor, it doesn’t mean I’m not a woman who’s also trying to have a personal life,” she said. “I’ve been in the city my whole life. I have a lot of relationships and spent time in the community helping people. When you become mayor, I’m realizing clearly now that that changes. I’m a human being, and I’m not perfect.”

Breed maintains that state ethics laws exempt her from having to disclose gifts from close friends. Breed and Nuru’s decades-long relationship, she said, predates their work together as top government officials and shields her from having to report the gifts, though she said in an effort to be transparent, she intended to report it on her next disclosure form.

But a separate San Francisco law also forbids government officials from accepting gifts from subordinates over $25 in value. Gifts under $25 can only be accepted “on occasions on which gifts are traditionally given,” according to a guide on city ethics laws written by the city attorney’s office.

Asked about the city rules, Breed said only that she was “definitely going to determine locally how this applies, and we will deal with it at that time.”

Supervisor Hillary Ronen and others have also held up the gifts as emblems of what many consider to be San Francisco’s culture of cronyism among top public officials, one that rewards personal loyalties and ignores potential wrongdoing — at the expense of the public’s trust in their government.

“This law is pretty common sense, that you don’t have your employees who work right under you pay and do personal errands for you,” said Ronen. “I mean, who would think that that was right?”

Ronen called for Breed’s resignation last week, after she said she confirmed her understanding of the gift-giving rule with the city attorney’s office.

“The culture of this low-level, ‘acceptable’ corruption in San Francisco is so entrenched, and so widespread. You hear the same things over and over: ‘You have to pay to play in San Francisco,’ and that is so deeply wrong,” Ronen said.

It’s not yet clear whether the city attorney’s office will separately investigate Nuru’s gifts to Breed. Breed said Tuesday that she informed the city attorney’s office about her relationship with Nuru following his arrest.

Breed could face fairly steep financial penalties if the San Francisco Ethics Commission concludes that the city’s laws were broken. Should the commission decide to investigate and find violations, Breed would have to pay three times the value of the gifts — nearly $17,000.

It’s not clear if any other agencies are investigating the gift. San Francisco District Attorney Chesa Boudin said his office would “investigate any potential criminal liability” that arises. A spokesman for Boudin’s office declined to specify what, if anything, prosecutors had begun to examine.

Dominic Fracassa is a San Francisco Chronicle staff writer. Email: dfracassa@sfchronicle.com Twitter: @dominicfracassa