New Zealand rescue teams suspended their search for a schoolboy who went missing Tuesday while caving with classmates and teachers during heavy rainfall.
The boy was part of an outdoor education class that "encountered a severe weather event" while visiting the popular Abbey Caves complex north of Auckland.
It was not clear how the boy disappeared, but police, fire and emergency rescue crews searched for several hours in vain before suspending efforts as darkness fell.
"The search is expected to resume at first light tomorrow and a cordon will remain in place this evening and overnight," Northland Police said in a statement.
Fourteen classmates -- aged about 15 to 16 years old -- and two teachers, all from nearby Whangarei Boys High School, were accounted for.
Police said family liaison officers and victim support had been assigned to assist the boy's family as they faced a long overnight wait for news.
New Zealand is approaching the austral winter and nighttime temperatures are expected to dip to 16 degrees Celsius (61 Fahrenheit) with rainfall expected to ease.
"Our thoughts are with the 'whanau' (family) of the missing child, as well as all those involved in the group outing and the school."
School principal Karen Gilbert-Smith said the ordeal had been "hugely upsetting for all concerned".
But amid anger and recriminations about why the group had chosen to go out in potentially treacherous conditions, she urged parents to be patient in a school Facebook post.
"In time we will seek to understand how this situation occurred, but for now I ask that we stay united," she said.
Abbey Caves are roughly five kilometres (three miles) from the city of Whangarei and feature three caves that "are prone to flash flooding", according to the council website.
Before the incident, information on the school website said their outdoor education policy was that a teacher in charge would check the forecast to decide if "the weather is suitable for the trip".