Crew members of the Polish state Tupolev Tu-154 which crashed at Smolensk yesterday were offered three alternate airports, as a result of dense fog, but opted to continue the flight in order to assess the weather situation.

Two Belarussian airports - Minsk and Vitebsk - as well as Moscow Vnukovo were suggested to the pilots, said Russia's presidential plenipotentiary representative Georgy Poltavchenko during a preliminary technical briefing with prime minister Vladimir Putin.

Poltavchenko, who was among the delegates waiting to receive the aircraft, states that he was informed that the weather conditions were "difficult", with visibility below 400m - and possibly as low as 100-150m.

But he says the flight crew considered they had sufficient fuel to continue flying to the Smolensk terminal area, to "look around, and then decide".

"Then we were told that they were going to land," he says, adding that the Tu-154 was not heard approaching before there was the noise of an impact. He says the sounds were "strange" and "not typical" of a crash.

Air transport regulator Rosaviatsia's chief, Alexander Neradko, told Putin during the briefing that visibility was below the minimum of 1,000m.

Neradko says the Tu-154 struck an 8m-tall tree at a distance of 1,200m from the runway. At this distance the tri-jet should have been at a height of 60m, he says, the standard for a 3° glideslope.

"The aircraft proceeded to strike more trees, broke up in mid-air, hit the ground and exploded," he adds.

No indication has been given, during the briefing, on whether the crew attempted to abort the landing. Earlier information had suggested that the Tu-154 had been executing a go-around.

Emergency situations minister Sergei Shoigu says that firefighting personnel were dispatched to the scene at 10:51 and that fires were extinguished 10min later. The aircraft came down about 300m from the runway, he says, with no survivors among the 96 occupants.

Transport minister Igor Levitin confirmed to Putin that the pilot "made the decision to proceed independently", despite the warning from air traffic control over the foggy conditions.

Polish president Lech Kaczynski and dozens of high-ranking Polish political and military figures were killed in the accident.

Source: Air Transport Intelligence news