As the news broke on Thursday that federal agents had seized the phones of five of Mayor Eric Adams’s top officials, City Hall officials hastily convened an emergency meeting.

The roughly 50 members of the administration who participated in the 3:45 p.m. call were told by the mayor’s chief of staff, Camille Joseph Varlack, that she understood that the developments would provoke anxiety. But she asked that they stay focused on serving New York City, according to two staff members who were on the call.

A few hours later, Mr. Adams addressed the F.B.I.’s seizures for the first time, resorting to what has become his go-to response in the face of mounting problems: He would “stay focused, no distraction and grind,” he said in a television interview on Fox 5.

But the remarkable avalanche of investigations and raids that struck at the heart of the mayor’s circle is no ordinary distraction, and it raised immediate questions about the mayor’s ability to manage the nation’s largest city amid an investigative onslaught now affecting much of his senior leadership.

On Wednesday, federal agents seized the phones of the city’s police commissioner, first deputy mayor, schools chancellor, deputy mayor for public safety and a senior adviser, and searched at least one of their homes.

The nature of the investigations, by the U.S. attorney for the Southern District of New York, is unclear, but it appears that one is focused on the senior City Hall officials and the other involves the police commissioner. The investigations are distinct from the same office's ongoing inquiry into the mayor and his campaign finances.