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.

The short flight on Tuesday was the fourth Proton failure in three years, and it was sure to raise safety questions among NASA officials and Western commercial clients of Russia's space services.

In recent years, the National Aeronautics and Space Administration has relied on Russia to provide transportation for American astronauts headed to the International Space Station. But those spaceflights have been powered by a Soyuz rocket that has a far stronger safety record.

The Russian space agency did not immediately offer an explanation for the crash.

There were no reported injuries at the site of the accident, an area that Russia rents for rocket launchings. But the short flight, instead of a journey to space, made for one of the most prominent rocket disasters in Russia's space program in recent years.

"According to the preliminary estimates from the Russian side, there is no destruction and there are no casualties," the Kazakh space agency, KazCosmos, said in a statement, according to Reuters.

In video of the crash broadcast by Rossiya 24, a Russian state television channel, the satellites appeared to break apart from the nose cone as the rocket tumbled to earth. The station estimated their value at $200 million.

In the live broadcast, the announcer noted as the rocket leaned over and flew horizontally, "It seems something is not right."

The announcer goes on to repeat that "something is not right," and added that "the rocket is now heading toward the ground and breaking apart in the air - and an explosion."

The crash was another setback for the Proton rocket, a workaday booster for the Russian space program that is used for commercial and military payloads.

The most pressing concern was the orange cloud, which owed its color to heptyl, a highly toxic type of fuel known as UDMH outside of Russia, that is used on the larger stages of the rocket. Kazakh authorities were cited by the Interfax news agency as saying they might evacuate towns, though the region is sparsely populated.

The Proton is one of the largest rockets used today, weighing 700 tons on the launching pad, according to a reference book published by the Russian space agency. A fully loaded Boeing 747, by comparison, weighs about 400 tons. Most of the rocket's weight is fuel.

Even after successful launchings, herders have found dead cows underneath flight paths, killed by eating grass that came into contact with jettisoned rocket stages contaminated with unburned heptyl.