Two Russian passenger planes crashed almost simultaneously late on Tuesday killing all 90 on board, and security officials said they were investigating a possible terrorist attack.
The planes disappeared from air traffic controllers' radar screens within minutes of each other and one, carrying 46 passengers and crew, sent a hijack alarm before crashing near the southern Russian city of Rostov-on-Don.
President Vladimir Putin ordered the FSB security service to investigate the crashes, which came before Sunday's presidential election in Chechnya where rebel separatists have threatened to disrupt the poll with violence.
"The fact that both planes took off from one airport and disappeared from radars around the same time can show it was a planned action," the Interfax news agency quoted an aviation source as saying. "In such a situation one could not exclude a terrorist act."
Witnesses on the ground heard an explosion on board the second plane, a Tu-134 carrying 44 passengers and crew, just before it crashed near Tula, 150 km (90 miles) south of Moscow.
There were no foreigners on board the planes, which both took off from Moscow's Domodedovo Airport.
"Around 11 p.m. (1900 GMT), give or take five minutes, there was this strange noise in the sky, then this torn-up book fell onto our garage," a local man told NTV television, holding up the book with its tattered pages.
HIJACK REPORT
News agencies quoted security officials saying they could not rule out a terrorist act, while Rostov prosecutors opened a criminal probe into the crash of the Sibir Airlines Tu-154 en route to the Black Sea resort of Sochi.
"A minute before the plane disappeared from the radar screens the interior ministry received a report from an air traffic controller that there had been an attack on the crew," Interfax quoted an Interior Ministry official as saying.
A Sibir spokesman said: "We are considering an act of terror as one possibility, especially after we received an automatically generated telegram from the Sochi air control center that the plane had been hijacked."
CHECHEN VIOLENCE
The incidents came against a backdrop of mounting violence in Chechnya, where Moscow has been battling separatists for a decade. Rebels launched a major raid in the local capital Grozny last week and have promised more attacks.
Moderate Chechen separatists denied any role in the crashes.
"Our government has nothing to do with terrorist attacks. Our attacks only target the military. This is part of the Russian propaganda plan to besmirch the struggle of the Chechen people," Farouq Tubulat, a spokesman for Chechen separatist leader Aslan Maskhadov, told Al Jazeera television.
The plane which crashed near Tula, operated by Volga-Aviaexpress, came down after nearly reaching its cruising altitude. The company said the plane was in good shape and its passengers had undergone all necessary security checks.
"I rule out pilot error, because even in the most serious conditions which can affect this kind of plane, such as loss of control or fire, the crew always has time to pass on information to the ground," Yuri Dmitriev, director of Volgograd Airport, told Russia's First Channel television.
An Emergencies Ministry spokeswoman said there was no chance of anyone surviving as the plane fell from 10,000 metres (30,000 feet). Wreckage was spread over several kilometres (miles) with some pieces about the size of a car, TV footage showed.
Three minutes after the Volga-Aviaexpress Tu-134 crashed, air traffic controllers lost contact with the Sibir Tu-154. Its wreckage was not found until Wednesday morning.
Emergencies Minister Sergei Shoigu told Russian television that nearly all of the victims' bodies had been found, and flight recorders from both planes had been recovered.
He did not speculate on the causes of the crashes, but said President Putin was being fully briefed on the crash investigation.
