City Council President Ed Flynn will be Boston’s acting mayor for 10 days while Michelle Wu takes a family vacation, her office said.

Wu filed a letter of absence with City Clerk Alex Geourntas on Wednesday, stating that she will be “out of town” until Saturday, Aug. 12 at 10 p.m. She left Boston at 10 a.m. on Thursday, temporarily relinquishing her mayoral authority to Flynn.

Per the city charter, the president of the council is acting mayor “whenever the mayor is absent from the city or unable from any cause to perform his duties, and whenever there is a vacancy in the office of the mayor from any cause.”

“Yes, I am acting mayor,” Flynn told the Herald. “It is in the city charter.”

Flynn will “perform the duties of mayor” while Wu’s “absence, inability or vacancy continues,” the charter states.

He will also preside over next Wednesday’s City Council meeting, which overlaps with his time as acting mayor, Flynn said.

Wu skipped town a day after announcing the city’s plan to “take a major step” to address the “drug trafficking, human trafficking and violence” that continues to fester around Melnea Cass Boulevard and Massachusetts Avenue — without stating what that plan would entail or when it would be shared with the public.

The mayor’s vacation may impact when details about the plan are provided. Her office declined to provide a timeline on Thursday.

Prior to leaving, Wu said the situation at Mass and Cass has “reached a new level of public safety alarm.” The danger there has led all non-city teams to remove their outreach workers from the area in recent weeks, the mayor said on Wednesday.