Russia said it would take part in the investigation of the crash of its first all-new passenger jet since the fall of the Soviet Union, a Superjet 100 aircraft that went missing on Wednesday about 40 miles (60 km) south of Jakarta.

It was carrying Indonesians including journalists and businessmen, eight Russians including embassy officials, pilots and technicians, as well as two Italians, one French citizen and one American, said Vladimir Prisyazhnyuk, the head of Sukhoi Civil Aircraft.

"We haven't found survivors," Gagah Prakoso, spokesman of the search and rescue team, told Indonesia's Metro TV.

Radio contact with the aircraft was lost at about 0800 GMT on Wednesday after it descended to 6,000 feet (1,800 metres) near Mount Salak, which rises to 7,254 feet (2,200 metres) above sea level, a rescue official said.

A rescue helicopter spotted debris on the side of the dormant Mount Salak volcano on Thursday, sending teams on a trek across steep and heavily forested terrain to reach the site.

A picture taken from the helicopter appeared to show that the plane hit the top of a wall of rock. Small pieces of white debris could be seen scattered down an exposed stretch of cliff.

The cause of the crash was not known.

"The airplane crashed at the edge of Salak mountain ... An investigation must be done immediately and thoroughly," Indonesian President Susilo Bambang Yudhoyono said.

President Vladimir Putin ordered Russian representatives to take part in the investigation, offering his "profound condolences" in a statement on the Kremlin's website.

AIRCRAFT FOR EXPORT

A senior Russian official suggested the crash was caused by pilot error rather than a technical failure. The plane was Russia's flagship jet and Moscow will hope the crash will not reduce confidence in its civilian aircraft industry.

"Experts are saying that the plane has been working impeccably well and that possibly it was human error," Deputy Prime Minister Dmitry Rogozin told reporters while travelling with Putin in Nizhny Tagil in Russia's Ural mountains.

He called the superjet a "reliable, competitive machine."

Superjet International, the Italian-led venture responsible for marketing the plane to the West, said on its website that Sukhoi's chief civil test pilot Alexander Yablontsev and his co-pilot Alexander Kochetkov had been flying the plane.

Yablontsev had accumulated 10,000 flight hours and commanded the Superjet on its maiden flight in 2008.

The aircraft made two demonstration flights on Wednesday.

It returned to Halim Perdanakusuma airport, east of Jakarta, after the first flight where some people got off because it was time for Muslim prayers and were left behind, according to Sunaryo from Sukhoi's Indonesian agent PT Trimarga Rekatama. Others who had not planned to fly got on board.

The crash was 45 years after a Dutch-built Fokker F-27 flew into a hill in the Philippines on a promotional sortie due to probable pilot error, said the Flight Safety Foundation.

"There have been losses on demonstration flights and they are not generally the fault of the airplane. But without more information it is impossible to know the circumstances here," said Paul Hayes, safety director at aviation consultancy Ascend.

Sukhoi, which has orders for 170 planes worldwide, plans to produce up to 1,000 Superjets, primarily for foreign markets.

It aimed to sell 42 planes to Indonesia, which is seeing a fast-expanding aviation market that aims to tap travel by a growing middle class in the world's fourth-most populous nation.

Indonesia's Sky Aviation signed a commitment last August to buy 12 Sukhoi Superjet 100s.

"Some of our staff were in the plane. We are waiting for the investigation by the authorities, whether it's human error or plane issues," said Sutito Zainudin, general manager marketing of PT Sky Aviation.

"We will take further action about the Sukhoi (purchase) after the investigation is completed," Zainudin said. A state-run newspaper in Vietnam said Laos was the first country in Southeast Asia to have placed an order for the aircraft.

The jet was developed with Western design advice and technology from companies including Italy's Finmeccanica (SIFI.MI), as well as avionics and engine equipment from French aerospace firms Thales (TCFP.PA) and Safran (SAF.PA).

Built in a converted corner of a Sukhoi fighter factory in Siberia, the Superjet was unveiled in 2007 as part of a drive to restore pride in Russia's aviation industry, but it ran into a series of development delays.

The Superjet 100, with a capacity of 68-103 passengers, is in service with Russia's Aeroflot and Armenian carrier Armavia and is half way through a 15,500-km (9,630-mile), six-nation Asian tour to try to drum up more international customers.

The aircraft is being marketed internationally in partnership with Finmeccanica subsidiary Alenia Aeronautica.

• A Permanent Economic Emergency