New York City officials believe they have stabilized a high-rise apartment building Wednesday in Midtown Manhattan after it began to buckle Tuesday.

The former Pfizer headquarters in Midtown has continued to move since emergency responders arrived, officials said Tuesday.

New York City has bet heavily on converting aging office buildings into apartments to help ease a housing shortage. But the threat of a partial collapse Tuesday by one such conversion in progress highlighted the significant challenges of those construction projects.

A major Midtown Manhattan thoroughfare remains gridlocked and seven surrounding buildings have been evacuated after two columns buckled inside a high-rise construction site, rendering the building highly unstable.

Two columns on the 21st floor of a building under construction in Manhattan buckled Tuesday morning, triggering a slate of street closures and a large emergency response, according to the FDNY. The FDNY said it got a call around 8 a.

Construction crews worked all Wednesday to prop up the Manhattan high-rise that suddenly buckled — but what caused the terrifying structural failure still remained a mystery. Temporary shoring and beams were completely installed on the afflicted East 42nd Street building’s 18th through 23rd floors during the morning after the structure stopped shaking and stabilized,

The 37-story Manhattan building was under construction when two support columns on the 21st floor buckled. Engineers are developing plans to reinforce the structure.

The operation to stabilize 235 E. 42 St. is expected to last "into the night," officials said.

A Midtown Manhattan high-rise building was evacuated Tuesday morning after authorities said it was at risk of collapsing. The 38-story building at 235 East 42nd Street was once the corporate headquarters for the pharmaceutical company Pfizer.