Malang, Jawa Timur, June 19 -- Park authorities in East Java have intercepted four people following an unauthorized expedition on the restricted slopes of Mount Semeru that left one hiker injured and temporarily stranded, officials said Thursday.

The incident highlights growing concerns over unauthorized tourism within the highly protected Bromo Tengger Semeru National Park (TNBTS), an active volcanic zone.

Rudijanta Tjahja Nugraha, head of the national park office, stated in Malang that rangers initially intercepted three members of the group-consisting of two local trekking guides and a porter-on Monday near the Taman Satriyan park management resort in the Malang district.

"Based on information gathered from the three men, one hiker ...