A man was arrested for lurking in the compound of the Central Java Police headquarters at about 1am yesterday.

The 31-year-old suspect from Blitar regency in East Java was carrying a backpack containing at least two knives, used syringes and a bunch of rusty nails.

Investigations are ongoing but the suspect, identified by his initials M.R., has been sent for a psychological examination, said Central Java police spokesman Djarod Padakova. "M.R. claimed to have jumped over the fence (of the police station) to search for food."

This latest arrest comes after two suspected terrorists stabbed and killed a policeman on Sunday after infiltrating a police station in Medan, North Sumatra. The attack took place at 3am, just as millions of Indonesians were about to celebrate Idul Fitri and mark the end of the Muslim fasting month of Ramadan.

Police reinforcements shot and killed one suspect and injured the other after they refused to heed a warning to stop. The suspect who died from gunshot wounds was identified as Ardial Ramadhana, and the one who was wounded is Syawaluddin Pakpahan. The latter had travelled to Syria in 2013 and stayed for six months while the Islamic State in Iraq and Syria was being established in the Middle East.

Although he had returned to Indonesia, Syawaluddin is said to have remained in touch with other fighters in Syria using the Internet.