OSLO (Reuters) - A Norwegian court sentenced a 17-year-old Russian citizen to nine months in jail on Monday for making a small explosive device and bringing it to the center of Oslo in April.

Prosecutors had sought a two-year sentence for the teenager, saying he had frequented Islamist websites, become radicalised and possessed images of Islamic State members killing prisonners.

The teenager, who denied any wrongdoing, said he had been planning to detonate the device in a forest near his home.

The device was placed in central Oslo on a busy Saturday night in April, one day after a truck attack in Stockholm in neighboring Sweden killed five people.

The Oslo police bomb squad said the device was about 30 cm (1 ft) across and appeared capable of causing only a small amount of damage.[L8N1HH0LT]

Soon after the discovery of the device, Norwegian police raised the country’s security threat level.

The teenager has lived in Norway since 2010 and has previously applied for asylum. The status of that application was not immediately clear.

In 2011, far-right mass murderer Anders Behring Breivik set off a car bomb in Oslo that killed eight people and destroyed Norway’s government headquarters, before going on a shooting rampage, killing 69 people at nearby Utoeya island.