Alexei Ratmansky, with family in Kyiv, leaves his ballet in Moscow.

The choreographer Alexei Ratmansky, the former artistic director of the Bolshoi Ballet who is now artist in residence at American Ballet Theater, was preparing a new ballet at the Bolshoi in Moscow when President Vladimir V. Putin of Russia made his announcement, early Thursday morning, that he had launched an invasion of neighboring Ukraine.

The ballet, set to Bach’s “Art of the Fugue,” was to have its premiere on March 30 but has been postponed indefinitely. The head of the Bolshoi’s press office, Katerina Novikova, when asked for a comment, pointed to a statement on the theater’s website, which says that it was postponed after “negotiations with the staging team.”

Mr. Ratmansky, who grew up in Kyiv and danced there early in his career, immediately decided to leave Moscow, and with the help of the Bolshoi, made arrangements to travel home to New York via Warsaw, along with the rest of his international creative team.

Mr. Ratmansky is Ukrainian and Russian. His parents, sister, nieces and nephews live in Kyiv, as does the family of Ms. Ratmansky, who is Ukrainian.

Mr. Ratmansky remains in frequent phone contact with his family. His parents, in their 80s, at first took shelter in the basement of their building in the downtown area, before driving to a small country house about an hour from the city. Other family members were taking shelter in underground garages and basements.

They are all safe for now, and, Mr. Ratmansky said, “trying to keep good spirits.”