The Mahakam II Bridge, meant to resemble San Francisco's Golden Gate, collapsed on Saturday [Reuters]

A bridge collapse on the Indonesian side of the island of Borneo has led to the deaths of 11 people, officials said.

Indonesian rescue teams reported on Monday that 33 people are still missing after Saturday's collapse of the 720-metre-long Mahakam II Bridge (also known as the Kutai Kartanegara Bridge). The suspension bridge over the Mahakam river is meant to resemble San Francisco's Golden Gate Bridge.

Witnesses reported hearing a loud crashing sound as the bridge connecting Tenggarong and Tenggarong Seberang districts in Kutai Kartanegara, East Kalimantan, buckled. A public bus, cars and motorcycles were seen plunging into the river in Kutai Kartanegara district.

Survivors could be seen swimming to shore and screaming in panic, while others remained trapped beneath underwater debris.

A witness told local television station TVOne, he saw at least one bus and almost a dozen motorcycles plunge into the river. Syaiful, the local witness also said "everyone was screaming" at the scene, which also included several mangled cars.

Still trapped

At 35 to 40 metres deep and with zero visibility, Sutopo Purwo Nugroho, spokesman for the National Disaster Management told the AFP news agency: "It's difficult to know exactly how many are missing because we don't know how many vehicles and people fell when the bridge collapsed".  

So far, Nugroho said 39 people have been injured and according to reports filed by members of the community, 33 are still missing.

Sunarbowo Sandi, head of the search-and-rescue team, said Monday some victims are believed to be trapped in buses and cars that crashed into the river.

Rescue teams will employ echo-sounding technology to analyse the bridge's underwater metal frame to ensure it is safe to start removing debris.

The cause of the collapse was not immediately clear but Nugroho said on Sunday that a steel support cable for the bridge, completed in 2002, snapped as workers were repairing it.

Indonesian President Susilo Bambang Yudhoyono has ordered an investigation into the collapse.