President Dina Boluarte of Peru was swiftly impeached and removed from office by Congress just after midnight on Friday, after a brazen shooting at a cumbia concert and mounting frustration over her failure to curb rampant crime prompted the parties that had long sustained her to withdraw their support.

Lawmakers voted 122-0 to remove Ms. Boluarte — the most unpopular Peruvian president in recent decades — invoking a constitutional clause that permits Congress to declare the presidency vacant on grounds of “permanent moral incapacity.”

Both lawmakers and demonstrators outside the building erupted in cheers. In a prerecorded statement released after the vote, Ms. Boluarte said, “At all times I called for unity, to work together, to fight for our country.”

The president of Congress, José Jerí, is next in line to serve as interim president until the general election scheduled for April 12, unless lawmakers elect a new leader from among themselves.

Ms. Boluarte’s ouster represented a sharp reversal by the right-wing and centrist parties that had effectively governed in coalition with her for the past three years, even as her approval rating plunged as low as 2 to 4 percent, from about 21 percent when her term started.

On Friday Congress approved four motions to impeach her with the support of parties across the ideological spectrum.