by Denis Sinyakov
BUCHALKI, Russia, Aug 25 (AFP) - Two Russian passenger jets crashed simultaneously in different places after taking off from the same Moscow airport, leaving 89 people dead and raising new fears Wednesday of terrorism in the heart of Russia.
The planes departed within about an hour of each other late Tuesday bound for destinations in southern Russia and went down at almost precisely the same moment 770 kilometers (480 miles) apart in two regions south of the Russian capital.
Russian President Vladimir Putin interrupted a vacation on the Black Sea and returned to Moscow on Wednesday evening, holding a meeting with the prosecutor general, who said terrorism could not be discounted in the incidents.
"We are looking at various possibilities, including a terror attack and other, technical problems," Prosecutor General Vladimir Ustinov said in televised remarks during a meeting with Putin.
In his first comments on the incident, the Russian president - dressed in a black suit and a black tie -- expressed his condolences to the victim's families and demanded "honest" information from his government about the investigation.
"We are gathered here now because of the tragedy," Putin said. "Before starting our work, I would like to express my condolences to the families and friends of those who died."
Russia declared a national day of mourning for Thursday.
Wreckage and bodies lay strewn across fields outside the central city of Tula and the southern city of Rostov-on-Don as more than a thousand emergency workers used cranes to sift through the detritus and extract corpses.
Two Israeli citizens were killed in one of the plane crashes, the Israeli embassy in Moscow said.
There were no claims of responsibility for the twin disasters and investigators also indicated that they were looking at other possible explanations including bad weather, pilot error and problems with the fuel pumped into the jets.
The Domodedovo airport from which the planes left said a total of 89 people were on board the two planes.
The "black box" flight data recorders from both aircraft were recovered and Russian news agencies reported that one of the planes had issued a distress signal before plummeting to the ground.
AFP reporters at the crash site outside Tula spoke to witnesses who claimed to have heard an explosion as the plane passed over their city, but their accounts offered little in the way of explaining how the plane went down.
Authorities in Moscow and Saint Petersburg, Russia's second city, meanwhile announced that precautionary steps were being taken to tighten security at the city's airports and other public sites with the participation of the FSB and other government agencies.
"All of the security services have been instructed to step up their vigilance," Moscow government spokesman Kirill Mazulin said.
An increased presence of police officers and other security personnel in public transportation stations and around many government buildings had already been in evidence over the past week.
A number of large public events, including a "Moscow City Day" celebration, were scheduled to be held in the capital in the coming days and security forces were carrying out frequent spot identification checks of people on the streets.
The heightened security in the capital and elsewhere reflected official concern that the vote in Chechnya, an election the Kremlin seeks to hold up as a sign of democratic progress in the embattled republic, not be disrupted in any way.
One key Chechen separatist leader, Aslan Maskhadov, has claimed responsibility for recent attacks on Russian soil and has vowed to sustain violent opposition to Moscow's political objectives for Chechnya.
A spokesman for Maskhadov however flatly denied the rebel leader had any connection to the plane crashes.
Chechen rebels or their supporters have been blamed for two major bomb attacks in Moscow this year, one that occurred in the subway during morning rush hour and another on a busy public sidewalk across the street from the Kremlin walls.
On Tuesday, four people were injured in a bomb blast at a bus station on the outskirts of Moscow. No one has claimed responsibility for that blast.
Meanwhile, emergency personnel said they had recovered dozens of bodies at both crash sites and were transporting remains to local morgues.
Interfax news agency said debris from the plane that hit the ground near Rostov was scattered over fields and forests along a 10-kilometer (6.2-mile) trajectory.