German investigators have revealed that the pilots of the Russian airliner involved in last week's mid-air collision with a cargo plane received contradictory instructions seconds before the crash.

They said voice recorders recovered from both aircraft showed Swiss air traffic controllers told the Russian pilots to descend, while the on-board warning system instructed them to climb.

	What went wrong?

All 69 people - including 45 schoolchildren - aboard the Russian Tu-154, and two crew members on the Boeing 757 were killed when the two aircraft collided at 35,000 feet (10,500 metres) over the German-Swiss border.

The revelation came as at least 1,000 people in the Russian city of Ufa, about 1,200 kilometres (750 miles) east of Moscow, attended an emotional service in memory of their dead.

Forty-five children from Ufa died when the Russian Tupolev crashed into a Boeing cargo jet last Monday night.

	:	Mid-air collision
How the crash happened

Russian President Vladimir Putin, on a visit to neighbouring Volga region, made an unscheduled stopover at Ufa's cemetery on Monday, where dozens of crash victims were earlier laid to rest.

Mr Putin told the widow of the Tu-154's captain that "the Russian pilots were not to blame for the tragedy", the Russian news agency Itar-Tass quoted him as saying.

Mr Putin said the Russian pilots "were professionals of the highest class".

Funerals

Shortly before Mr Putin's arrived, thousands of people gathered in Ufa's central square to pay their last respects to some of the victims.

Thousands of mourners attended the funerals in Ufa

Mourners crowded around 33 wooden coffins bedecked with flowers, many clutching photographs of their loved ones who had lost their lives.

At the memorial service, Orthodox priests and Muslim clergymen offered prayers for the dead.

Then the coffins were taken by bus to the local cemetery, where they were interred.

The BBC's Steve Rosenberg in Moscow says the tragedy has shocked Ufa and the country and there is growing anger as the investigation continues.

Conflicting orders

According to German authorities, cockpit warning systems told the Tu-154 to climb and the cargo jet to descend, just 45 seconds before the collision.

Skyguide says its controllers are under extreme pressure

But voice recorders reveal that one second later, Zurich air traffic controllers told the Russian pilots to descend.

The Russian crew did not respond, so the Zurich control tower repeated the order 14 seconds later, investigators say.

The Russian plane responded and the two aircraft collided 30 seconds later.

Although the aircraft were flying over Germany at the time, they were under the control of the Swiss air traffic control body, Skyguide.

Investigations are being carried out by both Swiss and German authorities.

The Swiss inquiry is looking into the possibility of homicide through negligence, which carries a three-year jail term for anyone found guilty.

The controller, who warned the Russian pilot to change course just 44 seconds before the collision, has been described as overburdened by a German team investigating the crash.