In another cultural casualty of the pandemic, the Upright Citizens Brigade is planning to close its two Manhattan locations, leaving the storied improv and sketch comedy hub without its own permanent space in the city.

In an email sent to students and performers on Tuesday, founders of the 30-year-old group said that they had made the “heart wrenching” decision to close its theater in Hell’s Kitchen and the training center on Eighth Avenue. U.C.B., which has long been a launching pad for up-and-coming comedians, has been showing signs of financial strain for over a year, having laid off staff and shut down its East Village venue.

The founders — Amy Poehler, Matt Besser, Ian Roberts and Matt Walsh — said in the message that they had already been struggling to pay New York’s high rents before the coronavirus hit, but the uncertainty created by the lockdown meant that they could no longer afford their leases. The message did not mention any threat to U.C.B.’s two locations in Los Angeles, but noted that even shutting down the two Manhattan locations would not be a “cure-all for the financial health of the organization.”

The severe impact of the pandemic on the group’s future was already clear last month, when all of the theaters and training centers went dark and the organization laid off broad swaths of staff members in New York and Los Angeles, including theater managers, bartenders and security staff. Online campaigns sought to raise money for laid-off employees on both coasts. (U.C.B. performers typically do not get paid, which is a sore point for many in comedy.)