London, Aug 29 - Abdullah Abdullah, Afghanistan's leading opposition candidate, has said the legitimacy of his country's new government is at stake because of what he described as 'state engineered fraud' at the elections.

'I think if the process doesn't survive, then Afghanistan doesn't survive.

'Because what does that mean? The same sort of regime that crafted this massive, massive rigging will be imposed upon Afghanistan for another five years,' he told The Daily Telegraph in an interview published Saturday.

'On top of whatever problems this government, this administration had, there will be its illegitimacy.'

Abdullah, the main rival to President Hamid Karzai, said he will exhaust all legal avenues to challenge alleged vote-rigging in the Aug 20 poll and if unsuccessful, would not recognise the elections.

'We will exhaust all legal avenues. But finally, if it worked, all well, if it didn't we will not accept the legitimacy of the process and then this regime will be illegitimate,' he said.