By Rupert Wingfield-Hayes BBC Beijing correspondent

China says it will put 2,000 specially trained police officers aboard domestic airline flights to protect against terrorism and other attacks.

Whole families were wiped out in the crash

Starting later this year, two uniformed and armed police will be aboard every internal flight.

China first announced it would put armed police aboard aircraft shortly after the 11 September attack on the United States, but the authorities seemed to be in little hurry.

But confidence in China's airline security was badly shaken last year when it was revealed that a deadly air crash was caused by a passenger setting fire to the cabin.

Dalian disaster

China's new force of sky marshals has been long expected, but for over a year, little more was heard of the idea.

All that changed late last year, when it was confirmed the deadly air crash in northern China was no accident, but was in fact a deliberate attack.

The plane plunged into the sea as it was coming in to land at the northern city of Dalian on 7 May.

All 103 passengers and crew were killed.

An investigation later revealed that one of the passengers had managed to smuggle a bottle of petrol onto the flight and used it to set fire to the cabin.

'Attacks on the rise'

Now, the new force is being rushed into service.

The state-run China Daily says all those selected must be quick-witted, brave and strong.

But few other details have been revealed.

Officers will, according to the newspaper, be uniformed and will be lightly armed.

China's air safety record is generally good.

There were a spate of hijackings in the early 1990s by people trying to defect to Taiwan.

But before last year, there were no reported attempts to deliberately sabotage an aircraft.

However, attacks on public targets are on the rise in China.

There have been a spate of deadly bombings in recent years, some blamed on separatist groups, others on madmen with a grudge against society.