MOSCOW — An unmanned rocket carrying Russian satellites veered off course and crashed a few seconds after liftoff early Tuesday, sending a cloud of highly toxic orange fumes toward the Kazakh city of Baikonur only 50 miles away.

Fears that the toxic cloud would waft into Baikonur were eased later in the day, however, after heavy rains dispersed the fumes.

Photographs posted online had shown the ominous cloud stretching over buildings near the launching pad, and residents of Baikonur, population 70,000, had been instructed to stay indoors and refrain from using air conditioners.

The Proton-M rocket rose just above its launching tower at the Baikonur Cosmodrome, wobbled and then tipped over into the desert in a ball of fire.