· Anger as shark cull begins in WA

Northern Territory police have shot and killed two crocodiles during the search for a missing 12-year-old boy taken from a billabong in the Kakadu National Park.

The boy was attacked by a saltwater crocodile while swimming with friends in the Mudginberri billabong, near Jabiru, on Sunday.

Another 12-year-old was bitten on the arm in the attack. He fought the animal off and survived and has been treated for cuts to his arms.

Officials have been up in helicopters and out in boats since early Sunday afternoon, with the search focusing on Magela Creek, which delivers water to the billabong.

Acting Commander Michael White say police believe the missing boy was taken by a crocodile as he and a number of other young boys were swimming in the billabong.

Police say they shot two crocodiles spotted by search boats overnight but found no human remains inside.

A helicopter will this morning fly over the search area, then boats will return to the water.

Police have also spoken to four of the boys who witnessed the attack.

Jabiru is located 200 kilometres east of Darwin.

A teenager fought off a five-metre saltwater crocodile in the same area about a year ago.

After that incident, people were warned not to swim there, but there have not been many attacks in the past few months.

It is the wet season in Kakadu, the most dangerous time of year to be swimming in waterholes and creeks.

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