SEOUL, April 2, 2008 (AFP) - South Korea's justice ministry Wednesday began drafting a bill that could punish child sex killers with the death penalty, amid rising concern over a series of recent crimes, officials said.

Under the proposed bill people who sexually assault and kill children aged under 13 would face either the death penalty or imprisonment until they die, the ministry said.

No one has been executed in South Korea for 10 years and activists have called for the death penalty to be formally scrapped.

'We began work today to get the bill ready for parliament approval in September as suggested by Minister Kim Kyung-Han at Tuesday's cabinet meeting,' said a prosecutor handling the case.

The minimum penalty for non-lethal sex offences against children will be raised to seven years, reports said.

The new bill was prompted by a recent case which shocked the nation in which two girls aged 11 and nine were kidnapped, raped and murdered. Their bodies were cut up and buried.

A suspect has admitted the crimes, police say.

In a separate case police Monday arrested a 40-year-old suspected paedophile for trying to abduct and rape a 10-year-old girl right outside her flat on the northern outskirts of Seoul.

The arrest came hours after President Lee Myung-Bak visited the local police station to express anger at their perceived negligence in handling the case.

'The latest negligence by the police has significantly angered the nation. The police again failed to protect the lives of the people,' the president said after his intervention.

Parents or private security guards have begun accompanying some children to and from schools. There have been growing calls from parents demanding harsher punishment for such offenders.