A Russian passenger plane carrying at least 170 people has crashed in eastern Ukraine and Russian officials said all aboard are feared dead . The aircraft, registered to St. Petersburg-based Pulkovo airlines, was flying from the Black Sea Resort of Anapa to St. Petersburg when it disappeared from radar screens over Ukraine.

Firemen work at the crash site of the Russian Tupolev-154 plane, east of Kiev, August 22,2006

Rescuers have already reached the burning crash site 40 kilometers northwest of Ukraine's eastern industrial city of Donetsk, where the plane went down Tuesday in severe weather.

A Russian emergency spokesperson, Irina Andriyanova, says first reports indicate lightning may be to to blame.

In comments broadcast on Russian television, Andriyanova also says the emergency ministry plans to send investigators to the crash site, as well as psychologists and medical help to deal with the aftermath.

Pulkovo airline officials have said there were around 40 children on board the plane, six of them two years old or younger.

Russia's evening news broadcast photos of the charred, smoldering wreckage strewn across a wide expanse of open field and advised viewers of emergency hot-line numbers for those seeking information about family members.

The crew reportedly issued an emergency signal seconds before disappearing from radar contact. Ukraine's emergency ministry spokesman, Igor Krol, says the crew then attempted to make an emergency landing, but the landing gear failed.

This is the second major crash of a Russian aircraft in as many months. In July, 122 people were killed when a Sibir airliner crashed after veering off the runway in Irkutsk.

President Vladimir Putin, who has been working from the Black Sea Resort of Sochi the past week, was notified immediately. Mr. Putin instructed Prime Minister Mikhail Fradkov to set up a state commission to look into the incident.

Tuesday's crash involved a Tupolev-154, which is considered the workhorse of the Russian regional fleet.